Security update of some sort effect cookies?

Does anyone know if a recent security update in IE / Firefox / Anivirus / Antispyware.. could effect cookie settings?

We use unique users to count of website traffic ( unique users )

I am thinking that cookies used to help count unique users might be effected.
I need to explain a drop in website traffic recently and i can't see anything that has changed apart from something messing around with the internal script that counts unique users.

Anyone know of a recent security change of some kind which might change the way cookies are handled which would have a large effect - i am thinking of a windows update / IE or Firefox update around early September.

Any help apprecated.

 

Sorry... i mean't,

We use cookies to count our website traffic ( unique users )

 

None i know of that will explain what you are seeing.

 

Anyone else know of a security update that could do this?

I am thinking of some kind of update which may effect a users browsers settings that control cookies or a change in the way a browser handles cookies, regardless of setttings.

 

Fine don't believe me.

More likely it's some variation due to search engine positioning

 

Yeah, unless there's a bug with the latest IE update (which is possible), it wouldn't affect it directly. I think it would be a really bad move on MS' part to try to set those things for people.. I'm also sure we would have heard something around here, too ("why doesn't Wilders remember my logon info anymore?")