A company called Peek today unveiled a mobile device built specifically to allow Twitter users to tweet.

Called TwitterPeek (nice branding!), the handheld device sells for $99.99 (which includes six months of service, and then $7.95 per month after) or $199.99 (with a lifetime service plan). It's being sold exclusively on Amazon.com.

TwitterPeek can be used only for tweeting. CNET News.com's Don Reisinger has some details:

The gadget lets (users) tweet, reply, retweet, send direct messages, and download followers. It supports one (Twitter) account at a time. Users can also view TwitPics by clicking the "view content" option from the TwitterPeek menu.

As the Peek blog suggests, TwitterPeek is targeting Twitter users who don't have smartphones and data plans.

Technically you can use SMS on a regular phone, but it's really not the same. So most Twitter users are stuck using the web -- and they're missing out.

The company points to this recent Rapleaf study of Twitter clients to make its case that most users are "stuck" tweeting from the web, but that could be a flaw in reasoning. I suspect the reason that 65% of tweets are sent from the web (instead of a Twitter-specific client or mobile device) is because people tweet a lot at work or from home at night. But that's just a theory; we'll see how this all plays out.

In addition to the black model shown, TwitterPeek also comes in blue. You can see a demo below of TwitterPeek by Engadget's Joshua Topolsky on Jimmy Fallon's late-night show. (I'm not sure how well it bodes that some members of the audience laughed when Topolsky explained that "all it does is send tweets and gets tweets back.")