According to their first post, you can expect to find news, behind the scenes photos, videos, and discussion topics when you visit the new page:
Welcome to the White House on Google+! Here you’ll find news from the blog, behind-the-scenes photos and videos, plus chances to engage with administration officials. One feature we’re really excited about are Hangouts. On our Google+ page, we’ll host regular White House Hangouts with administration officials on topics ranging from the economy to technology. Some Google+ users will be invited to join the Hangout with the White House and have a conversation with policy experts. But the best part is that even if you’re not “in” the Hangout, you can watch the whole thing live on WhiteHouse.gov, on our Google+ page or on the White House YouTube channel.
So you probably won't be hanging out with the President himself, but it looks like the administration wants to engage a new audience in policy discussions.
The White House has only posted twice today, but have already been added to over 7,000 circles. Their only other post is a video of Senior Advisor David Plouffe. Here, he discusses how you can interact with The White House on Google+ (and other social networks) following the upcoming State of the Union address:
The White House has already asked users what kind of discussion topics they would find most interesting. The latest comment asks "does the White House use plug in air fresheners of potpourri baskets," so, yeah.
Already a presence on both Twitter and Facebook, the Obama administration has spent the last year trying to expand their social media reach through other channels. In August 2011, Obama joined Foursquare and in October he joined Tumblr. And earlier this month, the Obama campaign opened up an Instagram account, hoping to provide voters an inside look at the trail through photos.