[Lucid:]

If you hover over your name or avatar, you'll see the url for your profile page appear. At the very end is u=(your user number here). You can also see this if you actually go to your profile. For example, I am 67, you are 1175, and Alpha is 3517.

And no, the join date listed on our profiles does not include the one from old Trisphe. That's another reason I haven't celebrated my Trisversary - I don't know which one to use!