Google Adwords keyword estimate

How accurate are they?

[rpking]

Recently my site has been either 1st or 2nd under a competitive keyword on Google. The description etc are all very appropriate to the search term, and the site is fairly well known and respected in its field.

By using the Adwords program, an advert for this keyword would get an estimated 1800 views a day. This is for the Exact Query Matching option.

However, total referals from Google, including other pages that get a steady trickle, are only approximately 25 a day.

Even taking into account automated searches (ie WPG reporting) etc., the click through rate seems very very low. Does anybody have any experience of this?

[rpking]

I have just discovered a possible answer to my own question, but it opens up a new can of worms.

If I perform a regular search for my term on Google, my site appears top.

If I then access Google through a US proxy (I'm based in the UK), my site is returned 29th.

This would explain the very low referal rate. How long have Google been serving varied results? Is there a chance that this is just a temporary side effect of the current update, or is it permanent?

If so, I'd better check all my keywords again via various proxies to see how their rankings are affected.