[Tails-dev] HTML5 + Canvas/font user tracing

There is a function in HTML to biuld bitmap images via HTML5 canvas element.
Every computer renders the images differently and this can use to define
an hash/id to deanonimize users.
The AddThis advertising agency using this feature For example... in youporn!

Some years ago... I was build a javascript that identificate via hash an
user:
Some characters are displayed into a SPAN element, coosing font-family,
size and unicode charaters.
It can deanonimize user. In a windows or linux machine you can get ad
unique in Intenret and in Tor (the same id).

A solution can be to change by a pixer (+1 or -1) the font kerning randomly.