I've been on AdWords for five days. According to the stats, all of my impressions have been on searches, none on content.
Welcome to WebmasterWorld, aplusses!
Some basic details:
When advertisers create new ads, or edit existing ads, those ads will show only on Google. Then, once they have been reviewed and approved, they can be sent to the search and content network as well.
How long it takes for ads to be reviewed is not cast in stone, and can vary significantly as traffic volume varies.
AWA