This is one of my new favourites. It was mentioned during a "Speed geeking" session at Lotusphere and as you probably suspect it enables you to exclude a lot of information from being logged to your http logs.

Especially with a lot of Ajax calls to the server it is very usefull to exclude some of them.

It can be found under Internet protocols/HTTP - On the right in the middle of the server document.

My server is a lot more responsive after this is enabled.

It requires a http restart to enable.