If you are trying to determine which site would be better for advertising, I would suggest you base that on your potential for return on investment (ROI) cost and not how much traffic each site has. First understand the demographics of the site - what type of users and does this match the kind of prospects you are looking for. Once you determine that the site matches your market, evaluate the cost of the ad by your typical click-through rate and conversion rate. This will give you an idea of your approximate ROI and if the site is worth spending your advertising dollars on. For instance, many of the internet marketing clients I work with get more traffic using Google Adwords, but have higher ROI from Yahoo Sponsored Search. Hope this helps.