We've already noted reports that Twitter is preparing to up its ad game by placing paid-for tweets right in the middle of your Twitter stream. Now we know the deadline for the changeover.

Promoted Tweets will start showing up in users' timelines within the next eight weeks, according to several sources who have been briefed on the matter.

Twitter has been aggressively courting advertisers in the last few weeks, assuring them that Promoted Tweets are no experiment. They won't just appear in Twitter search or HootSuite, as has been the case for the past year. Nor will they be banished to the sidelines of Twitter.com, the way promoted trends are. They're coming very soon, they're here to stay, and the company is looking into ways to make sure we'll see them — such as making the promoted tweets "sticky," so they stay at the top of the page no matter how far you scroll down.

If that sounds familiar, that's because it is. It's the same idea that Twitter had for its iPhone app — the widely reviled Quick Bar, rapidly dubbed the Dick Bar in honor of CEO Dick Costolo. Twitter seems to be betting that we'll find a Quick Bar much less intrusive on the web — which, given the amount of advertising we're subjected to on the average page, may be a pretty safe bet. (Twitter declined to comment for this story.)

What remains to be seen is whether advertisers will buy the idea and nudge Twitter into profitability. The site is expected to gross $100 million this year, far short of the $3.5 billion Facebook will be raking in from display ads.

What do you think? Will Twitter users revolt against sticky Promoted Tweets this fall as they did with the Quick Bar, accept them as a necessary evil, or perhaps even find them useful targeted advertising? Let us know in the comments.