The originally Blurtit site was founded by Tim O'Shea and Chris Lee, and I'd assume that either Tim or Chris were officially the first user.
The site has been through a few redesigns, and if you look at which user currently has the lowest user id, then you'll find that //www.blurtit.com/u/000001 belongs to John Swindells, the lead developer at Blurtit back then.
SO it's also possible that he's technically the first user of the current iteration of the site...
