How can I write this? (If you are comfortable, it is duplicated in the notebook) (part2) Social network - an online services for creating personal or corporate pages or web sites on a common platform designed to build social relationships and organization of information exchange. Catalog is classified by themes collections of sites, where the database is formed by people of manual selection of information from the Internet or when the site is sent to the show creators directory for inclusion in the Collection. Rating Sites is a directory with the condition that the pages in their database included software counter, and once the user opens the internet site, the signal goes into the database and ranking increases. Electronic mail - web sending text and files in the form of letters to a personal computer mailbox, a particular user for a confidential reading without publication (and sometimes with advanced functions, such as free e-mail on a public computer or a corporate mail). (part2)