Well, the problem is that multiple links from just one site aren't going to help you.
So for your FIRST comment at Digital point, you gain some credibilty with Google. But even if you make multiple comments, those extra backlinks (coming from the same site) aren't weighted the same in their algorhythm.
You have the right idea, though, just start spreading out your efforts onto multiple sites. Look for high page rank forums and high page rank do follow blogs and start getting backlinks from lots of them. I find these days that focusing on just about 10 high page rank forums and/or sites (page rank of 5 - 9) carries a huge amount of weight in Google's eyes. You don't have to do multiple comments on the forums - maybe just three posts to establish yourself as a member,then add your sig file, and then you dont' have to go back there unless you want to market directly to that community.
The high page rank forums don't necessarily have to be related to your niche, either. I'm getting incredible leverage these days from commenting on some high ranking software type forums (think Adobe, Mac users, security software users) even if my site is about, like, ferret bonnets or something. You should try to get SOME links though from sites directly related to your topic - and best yet, from an actual blog post where they talk about your topic. Comment on that. You can do a site search for your keyword to hone in on specific pages related to your topic to place a comment on. That saves time.
So instead of getting 1000 backlinks from just two places you really have to mix up your backlink sources to get credibiliy in the great G's eyes.
Other good ranking article directories with link power these days include articlealley, ezinearticles, searchwarp, and a few others - just do a search for your keyword in Google, see if any articles from articles directories come up, and try to submit articles to those sites.
Dan
