Same here, moreover: I've got friends and acquittances in Serbia, Bulgaria, Germany, UK, US, Spain among other countries, as well as through several states in my home country. Given that I have lived in 6 different cities around the world, and have made good relationships on each of those, I really like maintaining a "thin" contact thread with them.
Facebook does this really well for me. Before Facebook, I would have to "remember" to send an email, a MSN chat or even a postcard (around Christmas) to some of them. And the typical conversation through chat went "q: hey, anything new", "a: no.. no really". With FB I see when this people have had a noteworthy moment, and I can interact with them on that, even if it is just to say a quick hello.