It seems like lately, every time I turn around I am being invited to a new social networking tool by someone, somewhere, in a network I am already part if. There are literally hundreds of them out there. Some big, with multinational users across various platforms, some small, just getting started and focused on a specific category. The question is, which ones are actually useful, and which ones just offer a new and different way to suck time out of the workday?

Last summer, comScore released a study showing MySpace, Facebook, Bebo and Tagged all increased in June 2007 by dramatically huge percentages.

There's too many to even name here, so I won't try. LinkedIn, a business networking tool often called "Facebook for grownups" had over 14 million users back in September of last year when they introduced the ability to add user pictures; up from 10 million in April 2007. But Facebook let in grownups, too, and just seven months later total users had risen by 106%.

Then, to get into more of a niche, there's NikePlus for runners, Adholes for advertising people, BlogHer for women bloggers, and Pownce for alpha geeks. Just to name a few. And don't forget Flickr-hoo!. And it didn't even start out as a photo-sharing site.

More recently, the rise of Plaxo, Naymz, Spock, and Spokeo, most of which are in beta and are really social networking aggregators, trying to get you to use their site to maintain all of your networking contacts. Its almost as if the industry started saying, "You know, with all these networks out there that people have to keep up with, what if we offered a way to collect all of those contacts into one place and then get them to use US instead?

But now, how many aggregators does one need to participate with in order to master the art of online networking? And does having a profile on every single one of them help you, or just make you look like a modern jackass?

So, which if these can help you with your career? Hands down, number one is LinkedIn. As they improve the tools available, almost every day there is a new way for you to interact with your network. You can find people who went not just to your same university or school, but who graduated with the same degree. You can join groups for that university, for agencies you've worked for, or clubs and organizations you participate in (or at least list on your resume...).

The key to LinkedIn is you have a searchable profile whether you are actively looking for a new opportunity or not. It's the best place for people to find you and find out about your background, without the worry that your boss wil find that you've posted your resume and are looking for a new job. On LinkedIn, its a given that you and all your peers at work and even your boss have a profile, and probably link together and share networks. It doesn't imply that you are available to be recruited, even though that's exactly what's happening.

Some people think you lose credibility in an online focused workplace if you don't at least have a profile on the biggest and most used sites. And in advertising, there's some truth to this, I think. (Not to mention protecting your own brand from squatters...). Probably the number one reason people join new socnets is because someone they respect sent them an invitation, and we all hate to be left out of a party. But plenty of people in the digital world don't jump on every new and hot socnet tool to come around, and its not always because they're wildly paranoid about the universe they helped to create. Plus, many of these sites spam a user's entire address book, not fun. And "social network fatigue" has been on the rise for sometime, in fact, it probably led to the development of the OpenId concept.

So, recognize the timesuck factor. After all, if everyone in your network can see that you're constantly twittering or Superpokin' or sending out invitations to join something new, then you're not probably getting any work done, and that doesn't exactly make you a valuable employee. You don't need to be building your network to tell everyone you're just an empty suit, do you?

In recruiting, the mantra we often say is the best candidates have jobs they love. They are working hard and growing their careers. In an Open Source world, where the job market can go from feast of famine in a hurry, you need to be found and recognized whether you want a new job now, or not. Just make sure you're spending more time working than networking.