The slightly concerning thing is that the notice email I got was in my Spam folder. I checked the source carefully and the password reset link appeared to be legitimate. So I've used it (entering my email address only). The next email was also marked as Spam, with GMail saying that a lot of mail received from postmaster.scribd.com is spam.
Has anyone got any thoughts on this? Has scribd done something dumb in the past? Has their mail systems been compromised too? Is there a concerted effort to fool GMail into treating these password emails as spam?