I've noticed this sometimes as well. It might be site maintenance, or what/whomever hosts this site may undergo maintenance. If it's always at the same time, it would probably be on purpose.

As an active addin author, i must keep track of my addins if they are least downloaded and post addins every week. I do notice every time i open it and let it stay open for a while, it suddenly stops responding and I close it. But when i open the browser again, i have to wait for minutes for it to open again.Yes,there must be changes going on around here thats why this is happening. I hope.