buckworks - 12:44 am on Mar 8, 2013 (gmt 0)
AdWords remarketing by advertisers has nothing to do with Google Analytics; it requires special code snippets obtained from Google AdWords.
For site owners to remarket to you, they must actively create and retrieve code snippets from AdWords, actively place the snippets on one or more pages within their site, and actively designate ads to be shown to you sometime later.
Remarketing (retargeting) snippets can be mixed and matched to design a wide variety of followup ad campaigns.
When done skillfully, remarketing campaigns convert well, so advertisers are willing to bid higher for those impressions than in the average AdWords campaign ... maybe a little, maybe a lot.
As Netmeg alluded to earlier, skillful remarketing requires setting impression caps to keep the followup ads from being overdone. A smart advertiser will aim for enough impressions to create an occasional courteous reminder, without coming anywhere near "stalk the user".