Update: Here's what BlogRolling posted on their website:
We're seeing a problem between 2 and 4am PST each day that is causing Blogrolling.com to serve your blogrolls slower than normal. This is a regular but very puzzling problem. We're actively looking into the issue, but so far - no easy answers. I just wanted to make a note of this because I hadn't followed up on the system performance notice that I posted last week.So will I.
I'll keep you in the loop with updates as we learn more.

