Eastern Europe is the name of the region which encompasses the countries in the east of Europe.
The region is not strictly defined, as some of these countries fall into more than one area - for example Transylvania being part of Romania is considered a part of Central Europe, while the rest of the country is in Eastern Europe.
Eastern Europe is sometimes confused with the Eastern Bloc, which is a Cold War name for communist countries that were behind the "iron curtain". Eastern Bloc included all the countries of Eastern Europe, several countries of Central Europe and individual countries on other continents, particularly in Asia.
Russian is the traditional lingua franca of Eastern Europe, at least in countries constituting the former Soviet Union, but is increasingly being displaced by English and German as younger generations choose a more Western-oriented outlook. Eastern Europeans who do speak Russian are sometimes hostile to being addressed in the language, because they have unpleasant memories of being forced to learn the language (this is not the case in the Caucasus, where Russian schooling was optional).
The attitude in Eastern Europe towards hitchhiking is very relaxed. Money is rarely requested. Majority of the fast roads fall short of being western highways; walking and hitching on them tends to be OK. When travelling long distance, make sure you don't get stuck in the middle of a smaller village - walking out of it will take forever. Check with the driver, and get off either before, or better yet, after you pass the city. Most drivers will be nice to offer a ride to get you to the convenient location.