Kevin Werbach asks about free web site tracking services in his blog. Well, the easiest approach is, of course, to do it yourself.

It's not difficult. Here's the simple and extremely ugly shell script I'm using in order to get regular e-mail notifications about changes to web pages I'm interested in. All you need is a shell account on some Unix system somewhere around. In your home directory, you create a file named .webmind. Into each line of that file, you put the following space-separated information: Your e-mail address, "txt" or "html", depending on what kind of attachment you want, the URL in question, and a dot (which will be replaced by an MD5 checksum).

Once that's done, you just regularly run the script from your crontab - that's it.