Thanks Z038 and welcome to the thread. The behavior you describe is exactly what I experienced on the XP test PC without Flash installed. I guess I need to install Flash and see if the "Flash backup if you delete browser cookies" also works as advertised. I can monitor Flash cookies with the BetterPrivacy addon to Firefox.

Ken

Just throwing some things out in case you haven't tried them.

There is a program called BleachBit that might do a more thorough job of clearing cache and cookies.

The Firefox add-on BetterPrivacy detects and clears LSOs (Flash cookies).

Another Firefox add-on called Collusion shows you how all the web sites you visit are tracking you via third-party cookies. If you leave your browser up and let Collusion collect data for a few days, the resulting graph will shock you. Here is what Collusion says:

This one sounds really plausible... Maybe they are using "fingerprint" data. See this article: Race Is On to 'Fingerprint' Phones, PCs.

Thanks again Z038. I will look at BleachBit for regular use. I have BetterPrivacy and Collusion installed although I do not leave the browser running long enough for it accumulate any data. I will give the article a read.

Ken

Thanks Z038 for the link to the WSJ article.

It appears that some sort of fingerprinting is at the root of this issue. I suspect that if browser cookies and Flash cookies fail the sites are falling back on some sort of fingerprinting. Based on the fact that I am challenged when the Firefox version is updated on my CentOS machine I conclude that there is some incorporation of software related data in the fingerprint.

However, at two of the 3 sites of interest, once they have fingerprinted the computer on the Ubuntu Live CD they still recognize it when running knoppix. This leads me to believe that their fingerprint is strictly hardware based. The third site barfed when accessed with knoppix. I need to go back to Ubuntu and see if it is still recognized. Booting now...

The machine is still recognized when booted to Ubuntu. I have changed the CPU speed to "compatible" in BIOS. Rebooting Ubuntu. Well, perhaps not. It looks like Ubuntu is not compatible with compatible speed on an old Dell Pentium 4.

To summarize...

I have a snail mail letter in to the CIO at the large financial institution asking if their computer identification process is hosed or what data they are collecting but not disclosing in their privacy statement. I have enough $ invested there that I will have an answer from someone if they want my business.

I have an on-line contact message in to the major bank/credit card issuer again quoting their documents and asking WTF?

As to my local (small) bank... I am waiting for a return call from an "on-line banking support supervisor". Hopefully I will get someone who can at least spell PC I will update this post with any interesting findings.

Ken

I'm sorry but you cannot rope them together like that. Each site must be treated individually as they all use different rules.
There's no "magic cookie" going on here just rules based upon a few pieces of information and your inability to distinguish between how they are all used.