[development] Sign-up procedure

[Karthik]

In a site with ~33000 users, I found that about ~1900 sign-ups were
never completed and essentially clutter up the user table. I am
looking for opinions on the pros and cons, if any, of streamlining the
default sign-up procedure to:

a) Sign-up form only contains an e-mail field that the user fills in
to confirm authenticity.
b) The e-mail field is stored in a separate table along with the
sign-up URL token.
c) The sign-up e-mail contains nothing besides a sign-up URL which the
user clicks as opposed to the current e-mail which contains a number
of choices.
d) The user is presented with a web page where he selects his
username, password and assorted details (other than his e-mail for the
first time) and is logged in immediately.
e) Only after successfully completing step d) is the user account
added into the user table.
f) Perhaps an e-mail is sent upon successful completion of the
procedure for future reference.

Thanks,
-K