^ico,my e-mail account is attached with Ubuntu Forums,but I use different passwords for e-mail account and Ubuntu Forum account.
In this case is my e-mail account(under GMail) compromised???
no, it won't get compromised.
The only way your password gets known to them is if they manage to bruteforce a hash which will look like this:
Code:
1045abbc44f12ce0ada34721907ab34e
yes, that's true, but sometimes it's not just about password or your account compromising, sometimes it's about sending a message, some people just wanna watch the world burn...

on a serious note, though there's very little chances that they would try to decrypt that password, but there's more than that in it, they have a huge e-mail list now, enough for some mass spam message chain, they have your personal information which could be misused, it's not just about compromising an account, it can be about something more severe than that..