I was wondered whether there is a survey or report of the current state of browser compliance with the three Cookie specifications: Netscape’s original draft, RFC 2109, and RFC 2965 that obsoletes RFC 2109.
I know that, due to its age, Netscape’s draft will be supported by most clients. But some recommend not to use it any more, e.g. this tutorial on Apache’s HttpClient:
Netscape draft: This specification conforms to the original draft specification published by Netscape Communications. It should be avoided unless absolutely necessary for compatibility with legacy code.
So what about the other specification? Are they ready to be used yet?
The consensus seems to be that they still aren't ready to be used yet. Some of the reasons for that are mentioned here and mostly relate to browser compliance.
However, on a hunch, I suspect your motive for asking this might relate to the session hijacking problem that has been brought into the limelight by applications like FireSheep.
If that's the case, I came across an interesting paper proposing a solution to the problem called OTC's—one-time cookies. It might be worth a read. It's title is One-Time Cookies: Preventing Session Hijacking Attacks with Disposable Credentials and it's from 4 PhD students at Georgia Tech.
(In case that google Docs link doesn't work here's a direct link to the PDF.)
In summary, it basically concludes:
...
It's a very interesting read. I hope that helps someone in some way,
~gMale