You'll have to forgive Facebook if they woke up this morning thinking the sky was falling; if they were subject to the same avalanche of news, comments, and questions about Google+ as the rest of us were for these last 24 hours, it'll seem like they've already been condemned to the social media scrapheap. And in case Facebook needed any reminder of how quickly social networking pioneers can fall, Google+ was launched on the same day MySpace, once supposedly valued at $12 billion, was sold for just $35 million to an ad network.

As my colleague Josh Bernoff points out, however, it's a bit too early to write Facebook's obituary. First, we have to consider the fact that Google hasn't exactly lit the social world on fire in the past: Google Buzz was largely ignored, Google Wave was largely ridiculed, and even Orkut may be starting to lose its famous lead in Brazil. Then there's the fact that Google+'s key feature — the ability to organize your friends into "circles" and share certain content only with certain circles — isn't exactly new: Facebook already offers "lists" that let you target which content is seen by which friends.

So in a nutshell, a company that's never really succeeded in social media has announced a feature that other social networks have offered for years. If Yahoo had launched this, would anyone have even noticed?

Perhaps that's a bit harsh. In fact, as a consumer I love the circles idea. One of the smartest things about Orkut when it launched 7 years ago was its recognition — then unique in social networking — that not every friend is equal. Google makes the point that in real life we don't share the same information with everyone we know — and that our online social networks should work the same way as our offline ones. And that's undoubtedly true. I think the main reason Facebook's lists haven't caught on is that it takes a long time to organize an existing group of connections (one Saturday when I was bored, I organized my 400-odd Facebook friends into lists, and it took me hours) — but if you start with lists or circles from day 1, as Google+ is doing, it just might work.

If it does work then it'll be another step in "unleashing social from its chains," as Sean Corcoran likes to say, and making sure users can take their social interactions with them wherever they go online. This isn't a Facebook killer; instead, like Facebook's own Open Graph, it's another splinter in the social web — making it ever easier for people to access their networks and social content on any web site through any device. And that's exciting for users and website owners.

For marketers, though, it's somewhat less exciting. If Google+ and the "circles" concept take off, companies could have a much harder time reaching people through social media. After all, if users spend more time posting content to and reading content from just their circles of friends, doesn't that make it harder for marketers to get a message through? The more selective a user is in whom they listen to, the more likely they are to screen marketing out of their world. It's a growing fact of life in online marketing — Google's done something similar with its Gmail "priority inbox" feature, and Twitter's lists (as well as the lists features in Tweetdeck and Hootsuite) help people screen out non-essential messages as well. And fragmentation of social platforms doesn't exactly help marketers, either: The more unique social tools our customers use, the more time we spend developing for and managing different platforms. So if Google+ catches on, there's a real chance that social media marketing will become more difficult than it already is.

In the end, we'll have to wait and see how Google+ develops, and how popular it becomes, before we know the real impact on consumers and marketers. But for now, I think social media marketers have more to fear than Facebook does.