Simply because group decided to continue to stick with it instead of using Pathfinder, by Paizo Publishing. This was just because of some inertia, and not for some ideological reason: we've played to 3.5 for so many years that now it seems natural to continue.
I'm trying to make them change their mind, and although some of them like it, as a group we're still a bit too lazy... Maybe some day we'll start playing Pathfinder.
When we do, I'll start to publish Pathfinder-related articles.
I obviously don't want to give advice about a game I don't play on regular basis, so I'll stick to 3.5 for the time being.
I'm quite sure lots of people out there are still playing 3.5, so I hope this website will be useful at least to some of you.