This thesis is designed for better understanding the Google algorithm and influences of their constant changes on websites as well as SEM and SEO strategy. The whole paper will look at the websites that are related to tourism. When an entrepreneur starts his business, he must understand that a significant profit will bring him an online business that will reflect his main business. Nowadays, if a website is not active on the internet, as if it does not exist. The competition is fierce and there are more and more new entrepreneurs with new ideas, products and services which are shown on search engines. Here we come to the core of the topic of this thesis. Every website must be well designed, but above all it must have quality and be maintained continuously. Why? Considering the enormous number of websites in the sea of the internet, the most important thing for every entrepreneur is his website which should be at the top of the search results because it will be the only way for users to hear about it, to beat competition and to make a profit. Google's algorithms serve to give users exactly what they are looking for in a second when they typing a particular topic into search engine. Algorithms analyse each word and therefore find certain terms. SEM and SEO strategies help entrepreneurs make more profit and take a better location on Google search engine. These are strategies that can be pursued by entrepreneurs themselves, experts in this field or a certain amount of money is paid to make a website or ads appear at the very top of search results on a search engine. As Google's algorithms are constantly being updated, websites that use SEM and SEO strategy must also be modified and improved accordingly. In order to better understand the topic of these strategies, Google algorithms themselves and the importance of the website in the company, the continuation of this paper follows.