One thing that really annoys me about all web-apps (other than IlohaMail, AFAIK) that require users to be logged in, is that they generally only support one session per browser. Even GMail only supports one session, so whenever a friend borrows my laptop to check their accounts, they first see my mail, then have to log me out, log themselves in, and half the time forget to log out so I see their mail when I open up GMail again.

Supporting multiple sessions is NOT hard. If I did it with IlohaMail, so can anyone else.

(In case anyone's wondering why I use GMail in the first place... well, I don't, except as offsite backup, and as a reference for IlohaMail's prototype DHTML interface.)