There is no recommended minimum distance because the granularity of
the targeting really depends on the information we are able to pull
from an individuals IP address. For example, the Google IP address
only indicates ‘California’ rather than ‘Mountain View, California’.
In more densely populated areas, the IP information tends to be
better, so more granular targeting is possible; however, as a rule of
thumb, targeting larger areas (states) will be more accurate than
targeting portions of a city. My suggestion is to start granular and
see what kind of results you get. This will give you a good idea of
exactly how accurate the targeting is.

Finally, there are several good FAQs on location targeting in the Help
Center that may be helpful: http://adwords.google.com/support/bin/topic.py?topic=21.

Best,
AdWordsPro Sarah

On Sep 9, 1:30 pm, Mpls-baseball wrote: