I use facebook for showing my twitter updates (as most of my friends don't use twitter), showing my google reader shares (as most of my friends don't have google reader) and for event planning. The ability to easily share videos and photos also helps greatly. My last couple of birthdays were a little different and people took a little convincing. The hardest one was convincing people to buy into throwies, as you're "throwing money" around the city. Facebook make that possible without having to convince every single person myself. Once I got a group going they were convincing each other. And yes, everyone had a lot of fun. =)