Conservatives turn Obama re-election campaign's hashtag against the president

— -- Next time President Barack Obama's re-election campaign wants to motivate the Twitterverse with a hashtag, they might consider using one that doesn't have so much flexibility.

On Thursday night, the campaign took to Twitter as part of its push for Mitt Romney to release his tax returns, using the @BarackObama handle to ask people #WhatsRomneyHiding. And yes, they got the hashtag trending. But within a couple hours, something else was trending too: #WhatsObamaHiding.

The answers, to both questions and from both the right and left, ranged from political to fun and meme-worthy. We've compiled some here.

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