I think "lately" encompasses a couple weeks ago, tbh.
I like the idea of monitoring how many people are online - if it's more than an amount that makes it dangerous, maybe just pull the site down for a second and put up a splash screen, like Reddit does. That way we wouldn't have to go through the site being knocked down and having to get PPN to fix it, the splash would just go away once the visitor count went down.
Bonus points if the splash only shows up for guests. "PC is under heavy load right now, so guests are temporarily barred from viewing threads. Register today to have 24/7 access!"