I'm getting a new feature in Google Webmaster tools. The "Top Search Queries" section is also showing up number of Impressions related to that search query.

http://lh6.ggpht.com/_0qGhDLOwoFs/S8qTOLaz_SI/AAAAAAAABYU/lCPhvS4cE_o/s800/1.png

I'm seeing it too. It's very useful because you can expand the query and it shows you the different positions you're in for a keyword and then the number of impressions and clickthroughs for each of those positions...

Here's the official blog post:

<< Now you can click on a given search query in the Top search queries report to see a breakdown of the number of impressions and the amount of clickthrough for each position that your site’s pages appeared at in the search results associated with that query. Impressions are the number of times that your site’s pages appeared in the search results for the query. Clickthrough is the number of times searchers clicked on that query’s search results to visit a page from your site. In addition to impressions and clickthrough numbers, you’ll also see a list of your site's pages that were linked to from the search results for that search query. >>

http://googlewebmastercentral.blogspot.com/2010/04/more-data-and-charts-in-top-search.html

http://3.bp.blogspot.com/_pHpYpU4sgSI/S8YQY-s3sqI/AAAAAAAAAYE/zmjiWKPlZzs/s400/query-data-expanded-ds.png