This work focuses on web personalization, its advantages for users and merchants. Presents current standards in this field, analyzes theoretical background and technical realization. Finally describes application of the theory on actual web projects - Skrz.cz and Drakkaria.cz. Main benefit of this work is a complete overview of the web personalization and general manual for personalization implementators.

This thesis bridges the gap between two popular methods of achieving more efficient online experiments, sequential tests and variance reduction with pre-experiment data. Through simulations, it is shown that there is efficiency to be gained in using control-variates sequentially along with the popular mixture Sequential Probability Ratio Test. More efficient tests lead to faster decisions and smaller sample sizes required. The technique proposed is also tested using empirical data on users from the music streaming service Spotify. An R package which includes the main tests applied in this thesis is also presented.

Webbaserade kontrollerade experiment håller alltmer på att bli normen för mjukvaruföretagsom vill bli data-drivna. Ett av de vanligaste experimenten idag är A/Btester.Att få resultat från A/B-tester är enkelt, att få trovärdiga resultat är svårare.Även om forskningsområdet gällande A/B-testning är aktivt så finns det ännu ingenöverenskommen definition av nödvändiga förutsättningar för trovärdig A/B-testning.Denna uppsats presenterar en uppsättning förutsättningar och kopplar samman dessamed egenskaper för A/B-testningsplattformar. Resultaten visar vilka egenskaper enplattform ska inneha för att uppnå trovärdiga resultat. Uppsatsen presenterar ocksåen utvärdering av två vanliga A/B-testningsplattformar. Under denna utvärdering upptäcktesegenskaper som kan ha motsatt effekt på trovärdigheten av resultaten vilketockså diskuteras i uppsatsen. / Web-based controlled experiments are increasingly becoming the norm for softwaredevelopment companies who want to become data-driven. One of the most commonexperiments today is A/B-tests. While it is easy to get results from A/B-tests, gettingtrustworthy results is harder. Although the research field of A/B-testing is active,there is no agreed definition of the necessary conditions for running trustworthy A/Btest.This thesis presents a set of trustworthy conditions and connect these with A/Btestingplatform features. The results show what features to look for in platforms inorder to achieve trustworthy results. The thesis also presents an evaluation of twocommon A/B-testing platforms available today. During the platform evaluation otherfeatures were found that could have the opposite impact on the trustworthiness of theresults and this is also discussed in this thesis.

An A/B test is implemented on a SaaS rm's product page to examine the di erence in conversion rates from website visitors who are randomly assigned to two di erent product-landing pages that show di erent prices. To count as a successful conversion the visitors that view a product-landing page have to click on a \Free Trial" button. Half of the group will be assigned the treatment page, which will state higher prices and the other half will be assigned the controlled page, which will state today's current price. The only variant that will di er from the two pages will be the stated price of the product and all other factors will be kept constant. The controlled experiment is executed to get a sense of customers' price sensitivity, hence this thesis contributes to microeconomic research of the private sector, more specically to the ICT industry by using a novel approach with the help of A/B testing on prices. The results showed no statistical signicance difference between the two variations, which can be translated to accepting the null hypothesis; the demand for a particular Software-As-A-Service product will hold unchanged after the proposed price increase. At rst, this could be a surprising result but when looking into the industry, which the rm participates in and their early mover advantages this result could have been assumed.

The thesis in theoretical part explains the importance of optimizing usability for e-shops and describes the whole process optimization with a focus on user testing and A/B testing. Each of optimization methods is supplemented by examples from case studies. In the practical part thesis is focused on optimizing usability of specific e-shop Vivantis.cz. It shows the practical application of optimization methods with the emphasis on user testing and A/B testing.

When it comes to web-based user interfaces and web design, one of today’s trends is to use informative and storytelling animations. They can be used as tools for communication, simplifying the interaction, or guiding the user’s attention. However, those animations used in a web- based user interface can slow down the interaction and the user flow and become a distraction for the user. Three popular informative and storytelling animations that are used in web design are: background video, animated slideshows, and parallax scrolling. In order to understand what effect these informative animations have on the users’ reading comprehension on websites — four prototypes were created in Adobe Muse. A user study in form of an A/ B testing followed by a questionnaire were conducted, showing that the three different animations affected the reading comprehension negative. While they at the same time also brought an entertaining feeling to the user experience (UX).

This study investigates the impact of specific gamification elements in the Duolingo application on user experience, engagement, and motivation in language learning. Despite the widespread integration of gamification in educational technologies, there is a lack of detailed analysis on how individual elements—such as streaks, levels, XP, lingots, hearts, badges, and rewards—affect learning outcomes. To address this gap, we conducted A/B testing with two prototypes of Duolingo: one with gamification elements (Gamified Duolingo) and one without (Non-Gamified Duolingo). Six participants, who do not have Swedish as their native language, completed a Swedish lesson using both prototypes. The results indicate that specific gamification features significantly enhance user engagement and motivation. Elements like streaks and badges were particularly effective in motivating users to maintain consistent learning habits and achieve milestones. However, some participants found that overemphasizing gamification could distract from deeper learning. This suggests that while gamification can positively impact user experience, it needs to be carefully balanced to avoid potential drawbacks. The study's findings have practical implications for the design of language learning applications. Customizable and balanced gamification features are recommended to cater to diverse user preferences and enhance overall learning effectiveness. Additionally, timely and relevant feedback through gamification elements can sustain long-term user engagement. Scientifically, this research contributes to a nuanced understanding of how specific gamification components affect learning, emphasizing the importance of personalized and adaptive strategies in educational technologies. Future research should include larger and more diverse participant samples to validate these findings and explore the long-term effects of gamification on language learning. Investigating the underlying psychological mechanisms and adaptive gamification systems could further refine the application of gamification in education, ultimately leading to more effective and user-centered learning solutions.

Accessible web design is crucial for creating equal access to the internet for everyone. While numerous guidelines and standards exist to promote accessibility, it is often of low priority among professionals and unfortunately many websites remain inaccessible to people with disabilities. Accessible web design is often seen as a checkbox task, believed to decrease usability for people without disabilities, to result in less attractive designs, and be economically challenging to justify. Previous research has disproved some of these beliefs by demonstrating that accessible design enhances usability for all users. However, there remains a gap in research regarding the economic incentives associated with accessible design.  Therefore, this thesis aimed to investigate the impact of accessible web design on purchase intentions and customer experience. This was done by evaluating and redesigning an existing website for accessibility and subsequently conducting comparative testing between the two versions of the website.  The comparative testing consisted of A/B and user testing. Purchase intention was measured using statements derived from prior studies, alongside statements measuring concepts related to purchase intention. Furthermore, the customer experience was assessed using the After Scenario Questionnaire (ASQ), the System Usability Scale (SUS), and conducting user interviews.  The results show that accessible redesign positively influences purchase intentions and indicate that one possible primary contributor to this is an increase in information quality on the website. The customer experience showed no significant differences between the two versions, although user interviews revealed a small rise in user preference for the more accessible version.  In conclusion, this study shows that a redesign with a focus on accessibility increases user intentions to purchase while at the same time not decreasing the customer experience on the website. Hopefully, these results can contribute to creating a more accessible web for all users.

This study explores what potential influence on players’ gameplay experience in Soulsborne games could be brought by the design decision of removing the Stamina system, which is an iconic feature in Soulsborne games that puts a certain level of constraint on players’ in-game actions. A Soulslike game prototype with a melee combat system designed on the basis of Soulsborne games was developed for the research goal of this study. Two different versions of the prototype, with the only difference between which being the removal of the Stamina system in the second version, were used for playtesting. The survey data collected from a total of 24 participants suggests that most players were less concentrated during the in-game combats and experienced a smaller sense of satisfaction and accomplishment when achieving the in-game objective when playing the version that doesn’t have the Stamina system compared with the version that has the Stamina system. On the other hand, as also indicated by the collected survey data, although removing the Stamina mechanic might result in less fun for players, it might help players mitigate their frustration level in games, especially for players with relatively poorer gameplay skills.

The goal of this Master's thesis is to explain the importance of the Conversion Rate Optimization (CRO) at today's E-commerce market share. A lot of people in Czech Republic confuse this term with more popular and similar term: Search Engine Optimization (SEO). The CRO focuses on the particular website and its ability to meet the business goals. The goal of the CRO is to improve the website and its conversion rates for acceptable costs. The ROI is important here. The CRO is a broad topic so I focus only on one part -- A/B Testing. This technique is based on showing different variations of a specific web page to the users. They are divided among these variations. Each part can see different variation. In the result we can see which variation was the best in meeting the business goals. The goal of this Master's thesis is to thoroughly introduce this technique and the tool which is perfectly suitable for that -- Google Website Optimizer. It is free and worldwide known and used. This Master's thesis is divided into several main chapters. In the introduction I describe few marketing models that are closely related to the CRO. Then I focus on the CRO, A/B Testing and Google Website Optimizer. In the last chapter you can find a case study full of practical examples. So far there are only a few resources about CRO in the Czech language. That also demonstrates the fact, that the CRO is not much popular in Czech Republic so far. On the contrary in the USA or Western Europe these techniques are commonly used. Not only big companies like Google or Amazon.com, but even small businesses use the techniques of CRO and can profit from it. I think it is only the matter of time it becomes more popular also in the Czech Republic. Therefore I believe a lot of people find my Master's thesis very useful.