Updated with details on new Google+, Facebook features. In what's turning out to be a social networking arms race of sorts, Facebook and Google have traded big product announcements, including the full opening of Google+ and a number of news enhancements from Facebook. Google's also improved the search mechanism on its social networking service, while Facebook will introduce a "ticker" with real-time notifications of what friends are up to while they're using the service. Users will also be able to flag items like baby announcements, weddings and the like so friends who might not have signed on for a while can see them first thing. Google's made no secret that it wants to knock Facebook off its pedestal as ruler of the social networking space. It's not a small task: Right now, Facebook has 750 million users globally, while Google+ has about 20 million. Facebook should bring in about $4.3 billion during 2011 -- more than twice what it made last year. Google+ Our blogger Vincent Chow provides more details on Google's moves: First of all, if you've been looking for a Google+ invite all this time without success -- which was actually pretty difficult --  you can now join the club without one. Google+ has officially moved from field trial to beta, and they are now ready for the public. Just to make sure everyone knows about it, Google has even drawn a blue arrow pointing to Google+'s link on its normally clean homepage. (This is a graphic we're pointing to - don't be confused.) To those who're already in, you've probably seen Google+ Hangouts in action. Now Google has today rolled out several new features to make Hangouts even more useful. If you happen to own an Android 2.3+ device that has a front-facing camera, you can  join a Hangout right from your phone. Simply update the Google+ app to the latest version in Android Market and you're good to go. iPhone and iPad users will be able to do the same soon. Google also introduced more options to collaborate in Hangouts. You can now show whatever's on your computer screen to your buddies in Hangouts. In addition, you can share a sketchpad or a Google Docs document within the session. Further, it's now possible to give Hangouts a name, in order to define its topic. Lastly, you can now join as a spectator, provided the Hangout is on live broadcast. The "On Air" feature is now only available to select high-profile users. Two more things: In addition to the Google+ APIs rolled out last week, a new set of nasic Hangouts APIs has been released. You can check them out here. And -- wait for it -- Google has finally implemented search on Google+. Duh. Facebook The most noticeable enhancement is the real-time ticker that appears on the right-hand side of Facebook's front page. It tells you what your friends are up to on the service at that moment. It looks a little cramped at first, but you can increase or decrease its size by sliding its bottom border. New feature No. 2:  The top stories on Facebook's News Feed's are run at the top of your news feed and marked by a blue triangle in each item's top left. Click on the triangle to de-prioritize the item, or click on a blank corner to tell Facebook it should have been a priority. Over time, your feed should become smarter, as it were, based on  your feedback. At least on Facebook, users are taking note of the changes. Here's one that seems pretty typical of my friends:

How on earth does facebook get off thinking it knows which stories I would think are the "Top Stories from the Last Day"? Absurd. Just show me the posts in the order they arrive. Period.

On the other hand, notes the Detroit Free Press's Mark W. Smith:

While many will complain that this an invasive new feature, it's important to know here that Facebook is only displaying updates that were available to the user before. He or she may have had to do a little digging before to know that someone commented on a photo, but no new information is actually being shared here.

And, of course, every time Facebook makes a change millions of users make a hew and cry. On the other hand, 750 million is a lot of users, so those objections ay not be nearly as dramatic as they seem.