My own id is quite high, however... About a year ago I wrote a script to scrape Facebook users and their friendship information. I wanted to get the social graph of my university (Warwick), so I seeded it with me and a few random friends from the same school, and coded it expand nodes already well-connected to the network. It turns out that university students form a fairly tight international network, so my script starting scraping people from other universities, including some colleges in the US. Anyway, when I only had a few thousand users in the database, I noticed there was one with FBID 7 - Mark Zuckerberg's old roommate. Pretty cool how few hops were needed to get to him (and shows how FB managed to grow so quickly amongst the uni market).