Chrome's "autofill" for forms is a convenient feature, and it would be great, except that it 'leaks' information.
Websites which have forms to fill out can be a pain, and filling out forms is a pain, but what you see on the form is organized into "fields". You don't necessarily see all the fields. Some can be 'hidden' and get information from your browser you might not want the website to get. Pretty sneaky, imho.
At the gHacks link, there's a screenshot video which shows how it happens.
There are also instructions on how to prevent it:
- Load chrome://settings/ in the web browser's address bar.
- Click on "show advanced settings" at the end of the page.
- Scroll down to the "passwords and forms" section.
- Remove the checkmark from "Enable Autofill to fill out web forms in a single click".
I'd recommend removing the "autofill" feature and just doing it the old fashioned way, if you value your privacy and data.
Martin Brinkmann also made an interesting point, "There is the question whether browser add-ons that support automatic form filling may leak data to sites that use hidden form fields as well."
It's a good point...no answer just yet.