First is the large number of people on these sites. My Space alone boasts 100 million plus members. Facebook is growing in popularity, and Yahoo is already the number one site online and has been for years.

You can also waste a lot of time on these sites. With all of the fun things to do, like games (Yahoo), and videos and music (My Space), you can spend a lot of time just surfing around and goofing off on these sites instead of promoting your business.

That's why you may want to join one or two specialty sites. Unlike My Space, or Yahoo 360, on a specialty site, everyone is there for a specific purpose, or at least a specific topic. What's important here is that you won't have to deal with some of the things on a specialty site that you deal with on a general site. This includes too much content, as well as people who want to befriend you who clearly have no interest in the things you are interested in. Usually people who don't share your interests simply want to spam you with their offers, rather than taking the time to target their markets.

Here are three reasons to consider signing up for a topic specific social networking site:

1. Your market is much more targeted.

If you're a business owner who wants to sell more of your products and services, you're less likely to have to deal with those who are looking to make friends or find dates (Unless of course you offer dating services). Although there are some sites out there, like Christian sites, or dating sites, where you can make friends or find dates, most of these sites will be centered around the topic, not about building social relationships.

2. It's easier to find those you want to meet.

Since these sites deal with a specific topic, many will ask you to provide in your profile what you're looking for, as well as what you're offering. Although this isn't always necessary, or mandatory, it will assist those who are looking for you to find you. It will also help you find those who are looking for your products and services.

3. You may be safer on these networks than others.

Most social networks require that you do some kind of activation, which means that you have to provide a valid email address and confirm that you are joining. Some may even ask you to answer certain questions in order to qualify you before joining. Some sites you join may even require that you meet certain qualifications, as well as pay dues in order to become a member. The more exclusive a site is, the less likely your profile will be seen by those you don't want to associate with. You'll be paired only with those you want to meet.

Regardless of your reasons for joining a social network, whether it's for fun or business, you should try out different networks until you find the one that's right for you.