The Huffington Post is venturing into the wonky but increasingly popular territory of opinion poll analysis, purchasing Pollster.com, a widely respected aggregator of poll data that has been a major draw for the Web site of The National Journal.

The purchase is something of a coup for The Huffington Post, which has been making a more aggressive push into political journalism ahead of the midterm elections in November.

“It’s going to beef up our political coverage,” said Arianna Huffington, the Web site’s editor in chief and founder. “Polling, whether we like it or not, is a big part of how we communicate about politics. And with this, we’ll be able to do it in a deeper way. We’ll be able to both aggregate polls, point out the limitations of them and demand more transparency.”

The Huffington Post’s purchase of Pollster, which is owned by YouGov Polimetrix but hosted on NationalJournal.com, comes at a time of intense competition among media outlets vying for influence in Washington’s saturated online media market.