First let me preface by saying that i'm a web developer. I work in ASP, and i understand that php (which vBulliten is obviously written in) is similar.
Second, let me say that a friend of mine runs a vBulletin site. He doesn't have a sponsored membership the way this site does, but he runs his ads, and asks people to click on them to help support the site. But costs are high for him. With the amount of traffic he gets, performance can be a real problem sometimes. With that in mind I'll get to my point..
When you're on any of the forums, you have a title for each of the threads there -- or most of them. Each of those titles varies in size, but i'm sure there's a maximum. But the bottom line is that a whole lot of data is being sent down, just for the mouse-over to show the first couple of sentences of each thread. I did a little self-test on it, and the source of the forum that i checked was 97K. When i cut out all those titles, along with some of the extraneous "'s and empty tags, the inline CSS which could be put in a reference file.. it reduced it 17K to 80K. It's about an 18% reduction in size of that download.
Even limiting the number of threads per page would help keep down traffic some, and keep costs down.
Anyway, it's none of my business
I'm not a contributing member yet, but when i saw the mouseover bring up the title, i realized that a ton of extra and mostly unused data was being traffic'd around, and the computer nerd/programmer in me had to bring it up 
Take care
Second, let me say that a friend of mine runs a vBulletin site. He doesn't have a sponsored membership the way this site does, but he runs his ads, and asks people to click on them to help support the site. But costs are high for him. With the amount of traffic he gets, performance can be a real problem sometimes. With that in mind I'll get to my point..
When you're on any of the forums, you have a title for each of the threads there -- or most of them. Each of those titles varies in size, but i'm sure there's a maximum. But the bottom line is that a whole lot of data is being sent down, just for the mouse-over to show the first couple of sentences of each thread. I did a little self-test on it, and the source of the forum that i checked was 97K. When i cut out all those titles, along with some of the extraneous "'s and empty tags, the inline CSS which could be put in a reference file.. it reduced it 17K to 80K. It's about an 18% reduction in size of that download.
Even limiting the number of threads per page would help keep down traffic some, and keep costs down.
Anyway, it's none of my business


Take care