Just had some BTC stolen from this address. I used Chrome on Windows 7. Figured out what happened:
I googled "blockchain". The top result is a paid ad. This is what it said (sorry i am unable to cut and paste the image here):
Blockchain - blockchain.info
Adwww.blockchain.info/
Official Blockchain website with wallet, charts, statistics and more
It then takes you to the following site: blockchain.info.wallet.georgia.ru which is a phishing site. I did not pay attention to the url when I logged in since the site looked legit.
Should had used 2FA and ALWAYS double check URL's.
always use ad block (don't let any google ads through) and ghostery. Also switch to DuckDuckGo.com Much better than Google. They put privacy of users first and money second unlike Google.
edit: chrome is a browser by ad company. You are better off using FireFox or Opera