Snort is a program that detects network attacks based on signatures. I posted the link to Snort's site so people could figure that out themselves instead of looking stupid
I wrote some signatures for it that, instead of detecting attacks, detects Battle.net problems. If you look at the screenshot, you'll see that it sees failed logins and stuff.
And incidentally, Bleeding-Snort might be adding another rule set, specifically for games. If they do, Battle.net stuff will go in there.. We'll see!