Change detection and notification websites

[tigerstws]

I copied this from wikipedia::::

In 1996, NetMind developed the first change detection and notification tool, known as Mind-it, which ran for six years. This spawned new services such as ChangeDetection.com (1999), ChangeDetect (2002) and Google Alerts (2004). Historically, change polling has been done either by a server which sent email notifications or a desktop program which audibly alerted the user to a change.

The prevalence of cloud computing and smartphones is changing the CDN market, namely how polling is done and how notifications are sent.[citation needed] A mobile CDN device with a cloud back end does not suffer from limited bandwidth, storage or processing power, and notifications are delivered to wherever the device is.[citation needed] One such service is dasPing (2011)

Has any one actualy used any one of this companies and did it work? i used Google alerts last night and it did not work.

[ocabj]

Why not just write a Perl script using LWP to pull down a web page and run a checksum on the output and compare it to the previous script execution? If the checksums are different, then send an alert to yourself.

Then put this in your crontab.