First it claimed that I had disabled cookies, which isn't true. Then I cleared my cache and restarted the browser—still no dice: it still claimed I have disabled cookies.
I deleted all my cookie reject lists and tried again. At least I don't get an error message any more; instead, I get redirected to the login page.
A colleague said I should use Opera 7, which worked when he had that problem a while ago, or just wait a few hours. Or to use MSIE.
But I'm not sure whether it's worth the trouble. I don't want to use MSIE because I try to use it as little as possible in the first place, and if I use it because it's the only thing that works on Hotmail, then Microsoft Will Have Won.
And I use my Hotmail accounts mostly only rarely (the rest of the time they just collect spam). I have a couple which I intended to use for random spoofings, a couple were "tagged accounts", and one main account. I also used that when I wanted webmail, for some reason.
My colleague suggested I use GMX, which also has webmail, but I'm not sure. Especially since that side is also overladen with ads and I don't particularly like its interface, and since my accounts there are forwarders, so I'd have to turn off the forwarding every time.
On the other hand, I also have an account with Fastmail.FM, with which I'm pretty pleased. It gives me ad-free, lightweight HTML pages and seems pretty responsive. So maybe I'll use that for the times when I need webmail (I already started using it to keep track of my LiveJournal comment emails while I was away on a training course) and just ditch my Hotmail accounts entirely (or rather, let them lapse).
Still, it's a bit of a pity, since a couple of those accounts are very old—I think even from before the acquisition by Microsoft; certainly from the time when it was still possible to obtain a decent name-based nick without a bunch of numbers in it for disambiguation. *sigh*