Recent articles worth reading in The Wall Street Journal and The Washington Post comment on the fickle audiences of the Web's most high-profile social networking sites like MySpace and Facebook. Young people explain that the bad experiences they've had on the sites -- excessive spam, unwanted contacts, lack of privacy -- are adding up, and, coupled with a general sense that the sites are a fad, they are moving on. One high school sophomore even goes so far as to predict that people will get sick of social networking altogether and decide to "spend more time together" (gasp!). The big guns at News Corp, Google, and Microsoft, of course, see it a different way. They're betting not only that social networking will continue to grow in popularity, but that the "brands" of today will be the ones of tomorrow. Will they be right? Here are some quick tips to them (and anyone else considering a social networking site): Focus on niche markets. Facebook enjoyed success because it was "the student's social networking site." This made it feel exclusive and semi-private and kept out a lot of the spam and predator fears that plague MySpace. Facebook's decision to open up has created a backlash and could be costly if it's not managed properly. Other niche sites are popping up (for example, an old friend just launched hooah.com to focus on the military community) which could take root. Support small, private groups. Recently launched Vox is betting that bloggers and social networkers don't want to reach everyone and would much rather connect with just their friends and family. I think it's a good bet, and their overall potential market of users is much larger than those who want to broadcast to the world. There's no reason the large social networking sites can't do more to better support more private groups. Encourage real user investment. Not money, but time. Not time-consuming, but time-producing. It's easy to kill a MySpace page with hundreds of inane comments on it. It's harder to kill your Pickle.com account once you've uploaded, tagged, organized, and shared every photo you took in college. Make it hard to leave. Closed sites are so Web 1.0; but, let's be honest: you're running a business. I won't bail on LinkedIn when a copycat service comes along with a shinier logo because I'd need to convince all my contacts to jump too (much easier to do in high school). The best way to keep users is to offer things the competition can't, and this rarely involves just features and functionality. Make it easy to join. This is an old standby; but, it's ever-evolving. The user experience is the front-line of the member acquisition battle, and bad design (of user interface, the sign-up process, or functional implementation) can be a killer. #1 rule: it just has to work. Once that's down, collect data, study the data, and act on data to improve. There's plenty more to building and growing social networking sites; but, these basics cover some of the current challenges. One thing is for sure: the rate of change is dramatic and since millions of users can adopt and abandon these sites in a matter of months, there is no sure thing.