Social media marketing, has become increasingly popular recently because of its power of delivering large amount traffic in short time.
Before you start social media marketing you have to understand the types of social media sites so you can target sites you have to work with.
There are three main types of social media sites:
1. Social media sites where users usually have profiles and sometimes have blogs as part of those profiles. You could become known on such a site by building a profile for yourself and/or your company, writing a blog, commenting on the blogs of other users, and such. Becoming part of such a site means becoming part of a community automatically. Myspace, Zude, LinkedIn etc are such kind of sites.
2. Another kind of social media site is where you become noticed mainly by posting links, voting on links, and making comments on links other people have posted. Typically these are sites like Digg, Reddit, Slashdot, Fark, and many others.
You need to spend some time reading these sites to get a feel for their quirks and what interests their readers. These communities are usually hypersensitive to spam, so you want to be really careful about what you post. It's usually a good idea to hang around for a while with these sites before you start posting.
3. The third kind of social site is where users post links as bookmarks for themselves and to share with others. These sites may be a little less news-focused than the second kind of site.
Users tag their bookmarks with keywords to help the search engine determine the relevancy of particular links. As with the second kind of social site, you’re likely to see users voting and making comments on particular links. del.icio.us is such kind of site.
You probably already thought of this, many social media sites are a mix of these three kinds.