Impressions Data for Top Search Queries on WMT

[suzukik]

My question is about Top Search Queries on Google Webmaster Tools.

Impressions represents how many times your site has appeared. I remember hearing somewhere in this forum that your site doesn't necessarily have to appear on actual serps but only has to appear within 1,000 results;
because google can always see all the results(i.e. from #1 till #1,000).

Is my understanding correct?

[tedster]

An impression means that Google actually served a results page to someone that includes one of your urls.

If you are at #999 and someone clicks through to the last page of results, then that IS an impression. But if your url would have been on page two for the search, and the person doing the search did not click through to page two, then that is not an impression.

[suzukik]

So my pages must actually appear before users. I understand.
Thank you, tedstar. I always appreciate your help. :)