Well, this is interesting. As you probably know, Twitter yesterday made some changes to its Terms & Conditions, effectively banning third parties from inserting paid tweets into users’ timelines.

Further digging by Silicon Alley Insider and MediaMemo revealed that in addition, Twitter appears to also plan to start charging publishers and developers a cut of advertising revenue “where Twitter content is the basis (in whole or in part) of the advertising sale.”

If you’re interested in more details, Search Engine Land published a solid FAQ.

Hunch co-founder and investor Chris Dixon responded to the news (on Twitter, somewhat ironically) as follows:

Twitter is like a drunk guy with an uzi killing partners left and right. Expect investment in ecosystem to drop significantly.

Well it looks like the identity of the drunk guy’s very first victim is known: Twitter banner ad network Featured Users has apparently already put itself up for sale on Flippa.

There’s a chance that this is coincidental – the seller evidently doesn’t mention any of the above – but the timing suggests there’s a relation to yesterday’s announcements.

Featured Users, in a nutshell, is an ad network where Twitter users advertise their Twitter profiles on third-party Twitter applications and websites in order to gain exposure and ultimately, more followers. Developers and publishers can sign up and integrate ads into their website by including a simple line of JavaScript. Revenue is then split between the Featured Users ad network and the Twitter apps that serve the ads.

Whether Featured Users adheres to Twitter’s new T&C or not is not crystal clear, but even it does, it’s a dog. The service was only bringing in about $800 in net profits on a monthly basis, so you can imagine how interesting the business looks now that Twitter appears to be demanding publishers and developers for a cut of advertising revenue.

Unsurprisingly, there are no bids for FeaturedUsers.com yet.