Strange Google results

[HardCoded]

Can someone shed some light on the 3rd, 4th, and 5th results on this SERP?
http://www.google.com/search?sourcei...y+sound+webcam

The word "webcam" is not anywhere on these pages.

[cbp]

I stand to be corrected, but I think it becasue of the extra weight that google places on the first few words when you use several words in the search.

CBP

[arpecop]

You have to optimize for this word :) and there will be this result you need

[HardCoded]

Well..I don't really need to optimize for it, since I'm already at the top for 'Parry Sound webcam'. I was just curious about those other results...I always thought Google was an AND search by default, not an OR. It's returning pages that don't contain one term from my search phrase.