• by Mark Walsh  @markfwal, September 13, 2010

Sponsored posts are nothing new in the world of blog advertising, but until now, they have not typically appeared on PerezHilton.com, I Can Haz Cheezburger?, DailyKos, Wonkette, or any of the other sites that make up the Blogads network.

That changes today with the company's launch of a new "Adverpost" ad unit that runs between regular blog posts and is designed to mimic other blog entries except for the "Sponsored Post" notice that appears above each. The format comes in two sizes: a 400 x 400 image with text below of up to 1,000 characters, and a 200 x 400 rectangle with text of up to 500 characters to the right of it.

Advertisers can run multiple Adverposts on a single day or cycle through posts in episodic form to keep readers coming back. The sponsored posts can also include multiple links, and users can select which blogs the ads will run on. "We've wanted to do this for a while, since well marked advertorial is becoming more prevalent on various blogs," said Blogads founder and CEO Henry Copeland.

A short video on the Blogads site introducing the new unit suggests: "Online media is a giant cocktail party -- it's getting bigger and louder by the day." It recommends the Adverpost as a way to cut through the noise to "tell a great story." The new format debuts with a campaign by animal rights group PETA.

Blogads until now has offered standard banners as well as its own custom units, including a 150 x 600 rectangle that runs the length of a page on the right side and a 150 x 200 "Mini" box that runs in the upper right corner. Late last year, the company also rolled out sponsored "skins" in which the ad creative wraps entirely around the page.

Because the cost is expected to be at a premium to its other ads, Blogads is offering Adverblogs on a "share-of-voice" basis. So an advertiser, for example, can buy just 10% of inventory across a number of blogs in the network, which isn't an option for other formats. Publishers of individual blogs will set their own prices, but Copeland said he expects Adverposts to attract $10 to $30 CPMs, depending on each blog's audience size and niche.

One potential issue for Blogads with the rollout of the new ad unit: industry blog AdRants appears to have already trademarked the term "AdverPost" for its own sponsored posts.