Here are some notes on the numbers of results on search engines. Hopefully others will add to it.

Google does not guarantee more than 1000 results. (Nor do most of other search engines.) The first number of results you see is almost always an estimate - unless there are very few results for your search. You can imagine that lots and lots of computers take a look at your search and send in their suggestions, then a central "judge" tries to see what overlaps and provides you with the first few results and an estimate of the total number. It tries to do it quickly so it just guesses at first. You can notice that as you go to the second page or to the last page and press "show omitted results", Google tries to get a more precise answer, and the numbers may change wildly.

Google guarantees up to ~1000 results. If you see a number of results way more than that it's not something that can be trusted.

For a person who then goes to explore the links manually it makes sense to add keywords so that the number of results is under, say, 200. If you come up with a productive string, you should always do ""show omitted results".

For the lucky owners of add-ons like eGrabber or Broadlook tools - you may want to see all the 1000 results, since the software will dive into each link for you. To get beyond the 1000 limitation, you'd need to do some tricks such as add a keyword and use your string both with your keyword present or excluded.

-Irina