I think very strategic
SEO is a very good tool to getting Traffic to your Blog.
Specifically, I have found Squidoo Lenses very good for building quality Backlinks to my Blog. Which is good for
SEO.
Also posting comments to Quality blogs and Forums with Ancor text in your Signature has provided good Backlinks for me. Just as long as your comments or Postings have substance to them and relate to the topic at hand !!
I have NOT gotten too heavy in the Social Bookmarking to promote my Blog. I just think in the long run that
SEO and ultimately getting heavy Organic Search Engine Traffic to your Blog should be your ultimate goal.
And IMHO you should NOT spend many many months and spend many many hours trying to make friends at a Social Site in hopes that these people will go to your blog and be customers. Of course it is good for Backlinks. And in terms that is good for
SEO !!
But just make sure utilize your time efficiently !! And not get too bogged down in striving for more Social Bookmarking Traffic itself. Its a waste of time that could be spent towards getting Google Search Engine Traffic

The Real Traffic !!!