Re: missing cookie from/for www.perlmonks.com (sources)

[tye]

A cookie of "userpass=;" is one that is sent by PerlMonks when you "log out". The rest were indeed not sent by PerlMonks proper. There are a number of possible sources. Some were identified elsewhere in this thread.

So, malware/adware can insert advertisements and what advertisements get inserted can depend on which site you visit. So you only seeing these ads at PerlMonks doesn't guarantee that those ads aren't coming from malware/adware. And, yes, adware will make it appear that the ads (and their attendant clutter) are coming from PerlMonks.

This problem could also be a cross-site scripting problem. But that seems rather unlikely to me (especially as I'd expect more than just the one user complaining in that case).

The nice people at pair.com who host this fairly busy site for free also have a tiny hook that allows them to insert ads. Although, I'll admit that it has been a long time since I've seen any of them, when I did see them, it was just a single ad and the ads were never more than a single image and were mostly ads for pair.com itself. The main reason I allowed my ad blocking tools to block those ads was that there were several windows of time when the ad server could be much slower to respond than PerlMonks (which "is saying something", especially back then). I'd disable them for a while and then enable them again and then, maybe even months later, the ad server would get slow. Then eventually I mostly forgot that there were ads that I was blocking.

Having previously worked at the company of a top-100 web site that earned a fair slice via ads, I know that inserting ads into a web page has challenges and the methods used (because they scale in a number of important ways) can lead to the occasional inappropriate and even disruptive advertisement sneaking in. Such things can often do rather dramatic disruption and it looks like it is coming from "your website" even though the only thing that really came from "your website" was a small snippet of javascript that enables the insertion of ads from some ad network provider.

But I think that route is also pretty unlikely based on what you've described. I haven't even dug into things to find the ad-insertion hook to see if it is still using javascript. It doesn't look like it is, however, which makes it nearly impossible for this to be the source.

Middlemen, such as your ISP, could also do stupid things inserting ads. Perhaps you only see them on PerlMonks because we don't use https. That seems unlikely but I wanted to mention it.

So it seems to me that, by far, the most likely source is adware. Visit the site from a different computer (one you don't normally use and so is unlikely to have been infected with the same adware) and see if you get whatever junk you are complaining about.

Though, it seems rather rich for you to be complaining about this based on what several people seem to have figured out that were planning on doing "to us".