For instance, if the user is viewing a map of the.
For instance, if the user is viewing a map of the continental US then showing ads targeted at specific cities (e.g. Palo Alto) in the US is undesirable even though those cities of course overlap at the view port. On the other hand, if the user is looking at a map of Palo Alto, then we need to consider ads that are targeted at Palo Alto (city), SF Bay area (metro), California, Ameryka and any custom circle of polygon targets that significantly overlap the viewport.
Original text search at: www.seobythesea.com/?p=611