cline - 12:35 am on Jan 2, 2006 (gmt 0)
please correct me if I am wrong, the only ads that are enlarged type face are those that are site targeted at Google.
If your bid and CTR are good enough your text ad can be balloned to take up the entire ad space. I've seen this happen on Adsense-supported discussion groups where there are lots of page views. Presumably rotating single large ads generates more revenue than the same ads sharing space and getting more page views.