Social networking successfully takes a little finesse. On one hand, you want to be active, but on the other, you don't want to over-do it, and spam your friends. Users on popular social networking sites like Facebook and Twitter have plenty of options to block, delete, or "hide" you and your updates, and many of them will do it in a heartbeat, if you annoy them. Time is precious, and the relative anonymity of online interaction gives your "friends" the freedom to ignore you in ways they might not in person. So, here are a few ways to lose your friends online.
Ask for money, or try to sell them something. Think about it - Do you like it when your friends do this to you? Be honest. This applies to fund-raising efforts, too. If people are looking for places to unload money, all they need to do is answer their home phone and talk to the telemarketers - they don't need to log in to Facebook and find out what you're raising money for now.
Treat your "status updates" like they are your personal online journal. I know this is going to be painful for some folks to hear, but no one cares how you're feeling today. Yes, we know we should care, but we just don't. Sorry. Stream-of-consciousness journals are great, and can be very therapeutic, but there are better places to keep them than on Twitter.
Bore everyone with your politics. If you're a political activist, you'll definitely want to consider keeping an entirely different account for your online political activity from the one you use to keep in touch with your personal or business friends. Most people are only interested in politics the day before the election, and when you happen to touch on their pet issue. The rest of the time, they would rather talk about something else most of the time - especially if they happen to disagree with you. This also applies to starting arguments with people about politics - particularly on their own walls.
Send out several game, group, page, or application invites a day. This gets old. And sometimes these things aren't even secure, which REALLY annoys people.
Also see Mashable: 5 Reasons Your Online Chat Pals May Block You
Jennifer Pointer (e-mail) is in Tulsa, OK. She promotes a simple, a low-tech approach to effective online profile management, search engine optimization and social networking.