If you're just picking up a new Windows Phone, re-installing your favorite Twitter app or trying out a new one today (and for the next few days), you may have some problems logging in.
As happens from time to time, Twitter has changed their OAuth decompression method sometime last night and numerous 3rd party Twitter clients are affected. We're told by Scott Peterson, developer of the Twitter app glƏƏk! that it affects "...any Silverlight Mobile Windows Phone client that uses the non-PIN authentication, and doesn’t not expect a GZip response"
As a result, those devs will need to quickly make a slight change in their apps and re-submit to the Marketplace. That means for at least the next 3-5 days there will be issues creating initial accounts (if you already have Twitter setup, the apps will continue to work just fine).
Peterson also believes that Twitter could change the OAuth for PIN-based/Silverlight mobile clients as well in the next few days, which makes sense. glƏƏk! has been updated and submitted but it won't be available until early next week in the Marketplace.