One of the best achievements of the end of the 20th century has become the creation of the World Wide Web. Humankind had never before had such an easy and comfortable way to communicate with each other from any place in the world. The invention of the Internet has also brought the opportunity to find the answer to almost any question, but is the information from the global network are always undoubtful? Today, people can find practically any material for their study or work on the Internet. For instance, the biggest online encyclopedia Wikipedia can provide a lot of articles that answer for almost every common question in near any language. Another famous web-portal YouTube has billions of videos on any topic, not only for educational purposes but for entertainment, also. Another excellent example of a valuable Internet portal is TheAudioguide, where everybody can find the audio version of most of the books from all countries of the planet and any period of human history. How...