Adwords getting creative on broad matches?

Can't figure out why some search terms are pulling my adds up

[CernyM]

I'm getting some strange search terms pulling up my adds on Google that I don't completely understand.

I use broad match search terms with some negative matches thrown in there.

Let's assume that one of my ad groups is basically:

cotton clothing
-plus
-maternity
-discount
-cheap

My understanding of the broad match was that both keywords had to be in the search term for my ad to pull up. If that's the case, why are search phrases like

cotton top
women's cotton underwear
leisure cotton pants
cotton capris

pulling up my ads?

Its not that the hits aren't relevant (in most cases, they are at least semi-relevant), but that I'm surprised they are showing at all. Is this normal and expected behavior for Adwords? Would I have to go with specific or phrase matches to keep things completely focused?

[eWhisper]

This is due to G 'learning' as was posted in another thread. I have to run my keywords though the sandbox every couple days to see if there are more negative keywords to add (which is highly time consuming). I'm getting to the point that I'm only running keywords through when their CTR drops by more than 1% in a week as G is taking up too much time to maintain properly.

[skibum]

Its the new extended broad match feature that is causing your ads to show for terms you didn't purchase. There's a few threads floating around on it. Regular broad match doesn't exist anymore.