Social Media is a digital medium and as such it is extremely measurable. Granted there are a number of closed communities, but we estimate that around 80% is visible...
Whilst Facebook does not share its data unless invited, there are open pages. There is more to social media than Facebook of course, and a lot of it is just plain, open. Twitter, most forums and nearly all blogs are accessible and search engine technologies already read them - to your advantage.
Interpretation is keyBefore you start anything, you need to see what is going on.
Search engines are used to viewing a lot of data and search engines such as Google will help you find the data that you need. There are a range of dedicated and sophisticated tools out there that can help you develop your world view.
Examining the underlying data will tell you whether you are working with positive or negative sentiment. Clearly interpretation is key, but the first top tip is to find ways of examining the data. You cannot form an opinion if you do not have the data.
There is a lot that you can see, links to posts, comments on posts, comments via Twitter, Technorati, Facebook and Forums. They all add up to providing a world view and the amount of data available across a range of media - paints a picture that will direct your future actions if you take notice of what you find - and already we have experience and there are case studies out that demonstrate this is worth the trouble.