Which social media can you not live without and what new social media are you trying out?
For a very long time I was skeptical of the actual impact of Social Media on SEO. When Social Media first took off it was a very turbulent time online. All of a sudden submitting to directories became free when you usually had to pay to get into the best directories. Yahoo, for one, was very expensive and DMOZ was run mafia-style and if you didn't know the editor assigned to your section in DMOZ you were usually never certain if your submission would ever get approved.
Fast-forward back to Social Media, I have personally witcnessed what happens when you dump a majority of or entire presence from these sites:
What do I know and how do I know it? Well, because I actually dumped an entire web presence from all three at once and it's a very fast way for a website to go from page #1 to page #5 in 2 or 4 weeks time. Don't try that at home or anywhere else.
Beyond the current Social Media available what oher up-and-coming Social Media out there looks promising? Maybe something new in mobile marketing?