I have noticed a “drop off” in interest in social media as well. But, do you think that is because it has become:

1.) a main stream practice and has become a staple in the internet marketers toolbox?
2.) it is still in its infancy and the first real rise in it was due to the fact that it was so new and interesting?
3.) if interest in waining do you think that it will make a rise back into relevant tactics?
4.) People have not found a great way to monetize/track it?

I can see what you mean by the drop-off as emphasis on digg and other networks has dwindled, and many people don’t talk about it as a valuable tactic anymore. But I am assuming that many people still use it and see it as a valuable tool. These social sites are still very popular and obviously have some merit, even if just as entertainment value. Also emphasis on viral has dwindled a little as well but I think that is because it is unpredictable and often the stuff that explodes is not even related to a company or product. It is a science, albeit not an exact one, I think the best you can do is look at what has worked and, as with anything, follow the trends.

Dean