I hope you already know about BacklinkSpot. If not, BacklinkSpot is a famous DoFollow Blog Searchengine. You can search for DoFollow blogs which will give you a backlink for just commenting at them. Most visitors are Webmasters. The site is made popular Virally. Traffic is from various webmaster blogs and forums. The site receiving around 100 unique hits a day! All visitors are webmasters. There are currently 3 rotating banner spots(468X60) available. The banners will be placed below the searchbox. If you've a webmaster site/product this is for you. Price $10 per spot for 1 month.