I've been having a slow time selling ads directly on my site and thought selling text-links via Adsense would be a good idea (I already have Adsense on my site, but wanted to add instructions on how advertisers could take out an Adwords ad directly on my site). I tested it for myself- by trying to put an ad on my own page- by going through "placement targeting" and putting in my own URL, but it doesn't seem to work. I only get 300-500 visitors per day so I'm thinking this feature is probably limited to larger sites? It's a shame if it is, because Adsense would be a great way for smaller sites (like myself) to outsource ad sales and management.