Today Yahoo was acting oddly – on the “Sign in to Yahoo!” page it was reloading every second. The actual Yahoo.com or the my.yahoo.com pages were fine.
I then saw that Adblock Plus was turned off for some reason – I turned it back on and tried again. No change.
I recently changed some settings in CookieSafe and now chose to let Yahoo’s pages set cookies.
I was running out of ideas… except there’s this flash file (.swf) in the middle of the page and it doesn’t actually show anything. I’m sure it’s for storing data.
Blocked it with Adblock Plus… and now Yahoo’s behaving like normal.