Over the past several months, I've tried a variety of social networking tools. Some I've looked at and moved on, but some have become a regular part of my weekly - even daily - activities and successes.
The recommendations that follow aren't complete explanations. They are meant to hopefully intrigue you enough to try these different tools for yourself.

Of these three, I've been on
LinkedIn the longest. It allows you to connect and stay in touch with people you know. Have someone you've lost track of? LinkedIn might help. Want to stay connected with people who might move around? LinkedIn can help. While there is much more there, one of the ways I use LinkedIn is to ask questions. You can ask for input from those you're connected to or the whole community. I've used this for quick surveys, to get recommendations and more.
Facebook is the second largest social networking site in existence after MySpace and gaining on it quickly. While it originally was developed for college students, the fastest growing group of users is far past college age. Facebook allows you to search for people, connect with them in a variety of ways, add pictures, videos and much more. There are games and all sorts of diversions (proceed with the risk of time loss), but much of great value here as well. I have connected with people and consequently done business, been interviewed and more because (and likely only because) of Facebook.
Twitter is my most recent addition and definitely the hardest to describe. Some might not call it a social "network", but more like social publishing. Either way, it's definitely social. Often called micro-blogging or micro-sharing, Twitter allows you to post messages up to 140 characters long that are read by those who are "following" you. Alternatively, you can read the messages of those you follow. There are a variety of uses for this tool - many of which I haven't yet thought of! I have used Twitter to find products, resources and websites as well as meeting (in person) some really smart and interesting people.
These tools all can aid you personally and professionally. Like most things, in order from them to be truly helpful you will need to learn some things. Pick one (at a time) and give yourself a chance to learn enough to see how it could help you reach your goals. And by all means, when you pick one, connect with me. (Clicking on the graphical links will make doing that easy!)
Beyond these, there's another tool that is social networking-like that I love (though not the same or with exactly the same goals as any of these three). It's called One Degree Connected. Learn more about OneDegreeConnected from
my recommendation earlier this year.