Misreporting on Cookies
Hampering cookies by, say, deleting them frequently, can affect site traffic measurements, which, in turn affects advertising revenue (or will to a much greater extent in the future) because accurately measuring visitors, particularly new vs. frequent returners, will affect the revenue. Basically those who pay to advertise on a site want to know they are getting their money's worth and an ad seen by one person a 1,000 times is different than 1,000 persons once.
But to correct Buzz, spyware cleaners do not "massacre" cookies. They delete them. To further clarify, the five or six I am aware of, and Adaware and Spybot are my favorites, allow you to keep them if you want. In fact, only the full scan of Adaware identifies them for deletion and if you don't want to delete them, don't check the delete box. In Spybot, by the way, you can either remove cookies from the search in Settings or even put them in an exclusion list for the cookies you want the program to ignore.
Another condition I think Buzz is misreporting, in the sense that he is misleading you, is that "Firefox kills cookies on some regular basis." Firefox's options has settings for cookies and one setting is "Until they expire." Of course if the cookie is session only or the "expire date" is tomorrow, they might then be "killed" when you quit Firefox or when tomorrow comes, respectively. Of course, in those cases it is more accurately called suicide. You can set, I repeat set, Firefox to "kill" cookies, but Firefox is not doing it, you are. You can also purge them by hitting the "Clear" button. D'oh, that's you again! But you will get them again the next time you visit the site and they will persist according to your settings. Firefox is very user friendly, unlike that IE6, you know, from the company that does all sorts to make your computer do things they want but not what you want.
Cookies, to an extent, have a bad reputation but there are ways to use them to collect info you prefer them not to have. Most, however, are innocuous and even benevolent. Like the one my blog sets in your computer. Hah, you didn't know that did you. Yup, my template is set up to remember what text size you've chosen. If you need big text, it will remember that until you delete the cookie. Then the next time you visit, the text will start at 10 point again and you will have to up-size it again. If I remember correctly, that is all it does (besides withdrawing $10 from your bank account, hence no need for me to have a Pay Pal button! :-)
Other more benevolent cookies keep track of where you've been in the sense of a Google search which changes the color of links you have already clicked on. This is especially helpful if you are doing searches over a period of time.
Buzz links to a "screed" (Buzz's word, not mine) by A VC, who whines about the spyware cleaners, and swears he will never use them because, he says, it wipes them out and, although not specifically stating it, he implies he can't control that. He doesn't mention which one he uses, but let's be clear, he is disparaging the entire spyware cleaning industry and is basically clueless. Whatever.
The point is it is your computer and if you don't want cookies on your computer, it is your right to get rid of them using spyware cleaners. It is also your right to not use spyware cleaners. It is also the website owner's right to require them for access if they prefer. They can make you subscribe if they want, too.
Just so you know, there is a move afoot to stuff things on your computer to work around you deleting cookies. It's acronym is called PIE. This is news to me but I'm not a avid techie; put me in the highly casual techie category. From the explanation in the article, it sounds as though PIE allows for backing them up, letting you delete them and then putting them back. All without you knowing, if they don't want you to, of course.
You can read all about cookies here. You can read about why you may not like cookies,here just so you know what kinds of less than benevolent things cookies can do.