I logged onto TwitPic this morning, and was struck by the Twitter-like appearance of their new design.

[ Update: this design very quickly reverted, and has not been re-instated ]

It makes sense to create something that Twitter users will be familiar with, but consider how much Twitter have tightened control of their brand recently.

In contrast to TwitPic’s redesign, Tweetphoto recently became Plixi. They diversified by adding Facebook support, as well as events and location features. They’re clearly making the service their own, and shaking off the Twitter brand.

TwitPic have diversified too, adding events, location features and also face tagging. The difference being that their inextricable link to Twitter is unchanged, and now galvanised by the new design.

It would be wise for many Twitter-based services to reconsider not only their identities, but also their competition with Twitter itself. As Fred Wilson put it, “… the time for filling the holes in the Twitter service has come and gone“.

I bet Twitter would like to add photo-upload support to Phoenix, and get tagging into the bargain.

Twitgoo and Yfrog don’t seem to be changing tactic at all. TwitPic looks like an obvious contender for acquisition. They clearly don’t seem to be changing direction to avoid being made redundant – quite the opposite.