Until the mid 90s, spam was a non-issue. It was exciting to get email. The web was also virtually spam-free. Netizens respected one another and everything was very pleasant. Those days are long gone. Fortunately, there are some pretty amazing tools out there for fighting email spam. I use a combination of SpamAssassin on the server side and Thunderbird (with its wonderful built in junkmail filters) on the desktop. I am sent thousands of spam messages a day that I never see thanks to these tools.
But approximately five years ago, a new type of spam emerged which exploited not email but the web. Among this new wave of abuse, my personal favorite, comment spam.
I love getting comments on my blog. I also like reading comments on other blogs. However, it's not practical to simply allow anyone who wants to leave a comment, as within a very short period of time, blog comments will be overrun with spam generated by scripts that exploit sites with permissive comment privileges. To prevent this, most sites require that you log in to post a comment. But this may be too much to ask of someone who just wants to post a quick comment as they pass through. I often come across blog postings which I would like to contribute to, but I simply don't bother because the site requires me to create an account (which I'd likely only use once) before posting a comment. Not worth it. Another common practice is the use of "captchas" which require a user enter some bit of information to prove they are human and not a script. This works fairly well, however, it is still a hurdle that must be jumped before a user can post a comment. And as I've personally learned, captchas, particularly those that are image based, are prone to problems which may leave users unable to post a comment at all.