Therere some good services to find people in Russia, Ukraine and other post-USSR countries.
Odnoklassniki.ru project started in March 2006, and at that time portal contains more than 4 million users. The basic idea of the project is the creation of a database of users in educational institutions completed by users. You can find your old friends, former classmates and learn about for the moment, the kind of education received, which are working and much more. It is possible to send messages to people with whom lost contact, and possibly arrange a meeting with them.
vKontakte.ru is another good Russian social network with people search ability. You can search by the name, date of birth, city of residence, educational institutions (both search for schools to find all graduates of a school, clarifying results depending on the grade and year of production) and the workplace.
JoinFriends.com is Russian Service to help find lost friends, family, classmates, armed forces persons. List of search tools and message boards.