Where Do the Social Media Sites Fit In?
Facebook is currently the largest social networking site on the internet, and it is still growing. This means that more than a billion people have accounts, and they form networks and groups, add people as friends, and use the website to keep in touch and socialize.
If you want to do some social networking online, all you need to do is create an account with Facebook, Google Plus, Twitter etc, build up your profile, get acquainted with the features, and find like-minded people.
Find Like-Minded People.

The idea is to decide what you want to accomplish with social media, join the sites and then use the tools on each site to build up your profile. Once you do that, you can find people to add as friends, follow people, ad people to your circles. You can join networks, groups and communities.
If you have no clear idea what you want to do on the site, you can just create a general profile and view the profiles of others. The basic idea is to find people that you know or want to get to know. Even if you're using the site to further your business, you need to stick with this plan.
Ethics Of Online Social Networking.
You need to consider some ethics before you start with social networking. First, it is important to always keep in mind that social networking is very community oriented. You need to ask yourself whether your actions help support that community or not. If they don't, you could potentially be violating the unspoken rules of the site.
Basically, if you're interacting on social media sites in a manner that make people upset, angry, or sad, you're not handling it in a very ethical way. The same rules apply to both offline and online interaction. We should always remember that behind the profile picture there is a real person.
Another rule that is rigidly adhered to is the no-SPAM policy. It means that if you do something that can be interpreted as SPAM, then it isn't allowed. If you don't understand what SPAM means, consider what would annoy you. Constant sales pitches sent to your inbox? Getting posts on your wall all the time advertising products? These activities would annoy most people.
If you conduct yourself in an ethical and civil manner, and play by their rules, then you will make the community a better place. If you don't, your social networking will impact negatively on your business instead of enhancing it.
Life should be fun - enjoy it!

Henning Viljoen.
P.S. Learn how to create your online presence intentionally and leverage the best resources available.