A lot of websites, particularly newspapers and other publishers, are using a 3rd party tool to append, with Javascript, a trackable back-link to the original article that says something like "read more". This is OKish.. unless you're already going to attribute in a different format.
There's an opt-out for this on the tynt site: http://www.tynt.com/support/opt-inout/
I think it works via a cookie. It specifies "this web browser"
tags: javascript, disable, trick, browse