I've recently been looking at the count of a key phrase "frozen blue widgets" in comparison with what the Keyword Tool shows for that exact phrase.
I'm thinking this might be an interesting metric to check in with you all about.
For a well optimized site I've been working on for years which has a position 1 + 2 for the key phrase in Google, I get about 600 visitors per month which is 25% of the 2,500 that the Google Keyword Tool reports.
For a new site that I am starting with, the same calculation yields a visitors / GKT ratio of 10%.
Surely this will vary site to site / market to market etc.
I'd love to get some feedback from others on this.
Make sure you are using EXACT MATCH in the drop-down in the keyword tool - the stats for that will show you the search results for those exact phrases. Although, also remember that we don't know where Google gets those stats - they might not all be searches on Google.
If you really want to see how many searches Google does, then there is a way of doing it. I was disappointed about the traffic my site was getting for its key phrase, despite being #1 in the SERPS and having the exact-match domain, so I spent a decent chunk of cash and bought myself the #1 Adword position on that exact match search. Then I could log into Adwords and measure the number of impressions on that search. That was an accurate number of searches on that phrase.
The problem with this is, it's expensive. I was having to pay $20 a click to stay up there and guarantee 100% coverage to get accurate stats for a week.
After doing that though, I changed my entire strategy away from exact-match domains and key phrases and I'm now just optimizing for the long tail instead.
The long tail is getting bigger, the head is getting shorter.