Users of the Grindr smartphone application may have noticed an interesting ad scrolling across the bottom of their screens this weekend.

The ad, sponsored by Karl Rove’s conservative Crossroads GPS group, urges people to “Take away [President Barack] Obama’s blank check.” The ad also includes the Web address for NoMoreBlankChecks.com, which is paid for and maintained by Crossroads GPS.

The ad, a decidedly unsexy bit of advertising from a conservative group, feels out of place under thumbnail pictures of shirtless men. Grindr is a mobile social networking application that connects gay, bisexual or sexually curious men with other gay, bi or sexually curious men in their general immediate vicinity.

A tipster noticed the ad when it popped up (ahem) and dashed off an email to HOH.

“Speaking of blank checks, I wonder if [Crossroads GPS’] well-heeled funders had any idea their money would be going to this,” our tipster wonders.

To be fair to Rove and Crossroads, the ad in question is distributed across the world wild and wonderful Web by AdMob, a “mobile advertising network,” so the conservative group probably has little or no influence over where its ads are displayed.

“Web advertising generally targets the user, not the platform,” Crossroads spokesman Jonathan Collegio tells HOH. “Ads may run on thousands of websites and apps but are based on the user’s history and profile, not the platform on which the ad appears. So if an ad appeared on that platform, it was triggered by the user’s history and profile meeting the targeted demographic criteria, not the platform itself.”