I have been advertising on 2 websites. Site A brings in around 20k visits a month with 2.2 pageviews, and site B brings in 5k visits with 10+ pageviews. They both cost around the same. My site doesn't sell anything. So there is no conversion stats.
Based on the stats above, site B obviously brings in much more relevant traffic. However traffic from site A is not totally junk either, and it does provide a ton more traffic. If it comes down to the total page views I am getting from each of the site, they are pretty much the same.
Which would you choose if you have to advertise on just 1 of them?
[edited by: Raymond at 8:13 am (utc) on April 13, 2007]
Well - I don't know because I don't have ads on many sites - but if you are using Adsense I would use site a - the pages are not engaging the user, so they are more likely to click on a contextual Google ad.
If, however, you are selling ads on a CPM model of monthly fixed price, then you are more likely to attract above the line ads, who would want subliminal brand (banner) messaging rather than clicks per se. In that event, put ads on site b.