I was just telling someone about TinyURL and it reminded me of some math I did to calculate the number of unique identifiers they can create with the 36 alphanumeric characters they use for various lengths of IDs (check out the context of that comment).

In my introduction, I wrote, "it's even more than that, should they choose to have URLs with unique identifiers of between 1 and 6 characters". Reading this made me wonder: does TinyURL do this? And if so, what's the first TinyURL? http://tinyurl.com/0 doesn't exist (so subtract 1 from my answer ;-) but http://tinyurl.com/1 does. It is kind of fun to check out all these other people's URLs. http://tinyurl.com/z is pretty amusing.

I also realized that TinyURL's identifier is basically just counting in base 36. Ah, the ease of constructing unique IDs if they don't have to be hard to guess. 1...2...3...4...5...6...