multiple results from one site

how does that work?

[vampke]

Hi guys,

I noticed that a lot of my sites have multiple results in the SERPS. Usually Google puts them together, but not always.
Can anyone give me any pointers on how this works? It seems that most sites only get 1 result.
Obviously I'm quite pleased with this, as this can only be positive on my visitor stats, but I don't know what (if anything) I'm doing right.
So why do some sites get multiple results in the SERPS for 1 search term, but most don't?

cheers!

v.