[issa]

The obvious drawback that jumps out to me would be bombarding otherwise happy users with reports of your site going down. For example that 3am DB backup might have caused a 2 second outage (just an example...I'm sure we all know how to do DB backups properly) but none of your users would have even been aware of it without this "service".

That said, it would be useful in an application that people are counting on 24-7. But not sure how much of a market that would be. Not sure how much of a market there would be in any case.

[curbenthusiasm]

Hmm... I guess it could check, and if it's down, automatically check again in 5 mins to confirm. Or, you could turn it off at certain times, such as 9 pm to 6 am lets say...