I will be launching my social networking sites by 2nd week of May, 2009, but my greatest problem is which ads to upload on them. Affiliate ads, adsense or both?
That way you'll be able to get a grasp of what's working after the first couple of months.
Plus maybe you have 3-5 ad areas on your site, if you have them all as adsense then your site can look spammy so it's good to break it up with different types of ads
You can go with both adsense and affiliate ads. Just make sure that, on pages that have adsense ads on it, the affiliate ads should not look similar to adsense ads.