Google've extended their "suspicious account" activity alert feature to al Google Account users, not just GMail.
"If we detect any suspicious log in on any of your Google Account products, we'll display a notification on your Google Dashboard," notify Google.
"When you get this notice and if your account is compromised, you can change password directly from "more details" pop-up window. Or, if you know it was legitimate access, you can easily click "Dismiss" and remove the message. These notifications will hopefully help you identify suspicious activity but shouldn't be considered a replacement for best practices to keep your data secure," explains Google.
Also, using "report an issue" link at the bottom of Dashboard page, you can tell about problem or share your thoughts.