Don't know why but I thought the email was odd.
Perhaps because I have had a stumble upon account for a really long time now and asking for a user verification 1 year later just doesn't make sense
So I opened another Browser and logged into my account and there are no pending emails. Nor was there a verify your account message
So it is a SCAM!
So how do these people do this. Could it be that they just scrapped stumbleupon for user emails
Or is it my own email account that has been hacked
Either way, the message is BE ALERT. If it looks suspect, don't click it