Thank you for your input.
There was 1 email, so I suppose he couldn't access another time or simply didn't try.
Looking at my identifier I conclude that it was no accident. You can't just type in that thing by accident.
But then again, I've once typed in a valid private key by accident.
I'll change all passwords and perhaps move to a new wallet.
Cheers everyone
edit: I took a look at the email address, I wonder why I didn't do that earlier. It's a phishing mail. Here's a transcript:
--
Blockchain (
garyalanhill@comcast.net)
Authorize login attempt
A login attempt to your blockchain.info wallet was made from an unrecognized browser. Please confirm the following details are correct:
Time: 2014-09-15 09:17:42
IP Address: 91.241.18.129
Browser: Mozilla
User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.6; rv:32.0) Gecko/20100101 Firefox/32.0
Click here to confirm you own this account
Failing to confirm your account, may result in being suspended, according to our terms.
If this login attempt was made by you, this email can be safely ignored. It means you have visited your wallet login page using your alias from an unrecognez browser.
The login attempt was blocked, it does mean your wallet details are compromised
Top Tip
Backup your bitcoin wallet using dropbox. It's free, easy to use and secure.
VMIGHMSUJYYOETPUXBOQECVFNIISLNKHXVUNNG
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