I noticed that phpLD is still PR6. I checked the backlinks: It seems that there are 307,000 backlinks in Yahoo.. Doesn't this look strange to you too? Is "directory" keyword ignored by Google? Aren't most of the links relevant because of "directory" keyword? Any comments/ideas?
I suspect it is because the majority of links pointing to it are low PR. Remember that Google does not count every link from a single site too. So, it may only count 1000 links out of those.
If you do a backlink search you will see that maximum pr link is 5 lot of links but everything revolves around pr4-pr3 or less. Normally directories with pr5 or higher buy the unbranded script so no backlink,and on sitewides googles only counts 1 or 2 links the higher pr ones.