It was many years ago and definitely not a cloud service so not Distill Web Monitor. It didn't let me define fields to monitor, so not PageProbe.
I wouldn't have used a cloud service. What's the point? My browser already have everything it takes to download pages and diff them. I understand that if the computer is off the browser won't monitor the page but it was ok with my use case: if it's off I won't be able to react to the CVE.
And for other use cases, it's no business of anyone else but me to know what I'm monitoring.