I noticed on the home page that there are folders for different categories and languages... and some display yellow and a few are gray... why is that?

And don't say this question is ridiculous.... i am curious!!

I think the yellow folders are the ones you have never posted in.

Or the amount of articles in them... i noticed that the grey folders have less than 10,000...

That could be the answer... unless Dani has a solution...

Yellow means they contain unread posts.

... then wouldn't all of them be yellow?

okay... then that'll make sense... in a way...

It's an indication of whether the forum is already all read, or contains unread posts. A forum becomes read in one of three ways:

  1. You've actually read all posts made in the forum within the past few weeks.
  2. You've marked the forum as read by clicking on the 'Mark Forum Read' link or double-clicking the yellow icon to turn it grey.
  3. You've read the newest post in the forum. A forum is considered read if you've read the latest thing it currently has to offer.

What if I am only hanging around the php and web design categories... why do the others show up yellow?

Because there are new since either the last time you visited the forum or a few weeks ago, whichever is later.

okay... makes sense