I looked in my e-mail going back a few days and saw the above e-mail. It looks legit, right? It appears to be coming from a twitter engineer, but look at my mouseover...there's a different URL behind the one showing and it looks to be suspicious.
I've gotten six of these since April 21st and I know that they're phishing-related. Most people don't know this, though. While some people suspect this type of e-mail is suspect, others are asking, "WTF is this?"
1. Turn off HTML rendering in your e-mail client, as this prevents accidental clicking of malware/spyware/phishware links.
2. If you prefer HTML rendering to be on, if your OS or e-mail client supports link mouseover, you should be able to see what site you'd be directed to if you clicked the link. If the link isn't related to Twitter, then you know that something isn't right about that e-mail.
These phishers are beginning to get crafty, and in a subtle manner. It's sad that we have to suspect any official e-mails as bad as a first step.
Bottom Line: Don't click on those links if you're getting these types of e-mails.