I have nothing against using social networks to promote your business. I do it and while it doesnt necessarily translate into sales, I do get more interest in my work. And even better I make new friends.
But what I do have a problem with is SPAM. No you're not emailing me directly to tell me about your latest pyramid scheme but I really don't want to open my Facebook mail and find a link to your latest "Money Making Video". I don't want to see that on Twitter, or MySpace, or any of my memberships on Ning.com. Another pet peeve, stop tagging me in videos I'm not in. This is a new trend I'm seeing on Facebook. If you want me to watch your video, send me a link. Oh that's right I'm not interested in your emails either. **sigh** I guess you need a new marketing strategy.
Just an aside, if you have a legitimate business (not a scheme) you want me to check out, email me, tweet me, etc. I have no problem with supporting fellow artists and business folk. I often blog about shops I like and don't mind blogging about you if I like your stuff. We can do a link exchange...we both win.