If your on Twitter and use Ubertwiter then you may have seen this post:
So I contacted them and here is their reply:
From: UberTwitter [mailto:firstname.lastname@example.org]
Sent: Tuesday, July 20, 2010 8:54 AM
Subject: Re: Feedback from @securid
We collect this info for two reasons, first the PIN is used for subscription services, i.e. to turn off advertisements. The lat/long is use to improved our location service and is covered in our terms & conditions. Email is never filled out, and we will be removing phone number as there is no reason to have that. Thank you for pointing this out.
follow @ubertwiter for updates
A very nice and fast response. Remember some companies want to do the right thing, we just have to ask.