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There are TONS of case studies of blog comments ranking terms alone.  I wouldn't suggest it as a long term strategy, but to say they don't work is disingenuous.

Not sure what the policy is here on linking out to other forums as I don't come here often.  And i'd down vote anything that is factually incorrect.  Arguing is fine, but sharing disinformation based upon the echo chamber really helps no one.

I know buying links is frowned upon by many, but it works amazingly well.  In fact, post-Penguin blog comments work even better than before.

There is an unaffiliate WSO launched that ranked youtube videos in under 24 hours using just OneHourBacklinks.com.  Ryan Deiss at the Traffic and Conversion seminar (and in their private membership area) use this as a central ranking method for all of their clients and e-business students.

We didn't know who either was prior to their announcements and they both showed extensive proof.  And neither is an affiliate - these links just work.

Again, I don't recommend this as the exclusive link building method (even though they do).