Have been having trouble with my site since mid november that if i do a site:www.domainname.co.uk then it lists most of my site (500 pages) as URL only. Everyday if I do a search for a particular phrase which is on everyone of my pages and is unique to my site it picks up anything from 10-40 odd of my pages with the cached info. These pages pretty much change every day or so to different ones on my site and the others drop back to URL only. It is though it can only list fully a certain amount of my pages.(my homepage is one that is always listed as URL only and has stayed at PR6 the whole time)
My site has been live around 2 years and has ranked well prior to this and dont think I had any server problems.