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.
Helpful post. You are 100% correct. Anyone that wants to can run any search and if they get over 1000 results (and if they have their Google Preferences set to return 100 results per page) they can go to the bottom of the page and will notice page numbers 1 - 10. Click on page 10 and you will see there is no Next button any more because the engine only returns the first 1000, like you say. Another indicator is the result count. Whenever you see Results 1 - 100 of about X,XXX that is your cue to work on your string. It is the word "about" that lets you know. Whenever you have more than 1000 you need to add skills, title, industry, and geography keywords to get those results way down.