I really like this idea, but. I've been thinking about this, and also the fact that Pingdom, etc. seem to consolidate. Is there really a big market for "simple monitors"? If you are small, you probably don't care much/do it yourself/don't want to pay. The moment you grow bigger, you have many more comprehensive options available to you like Sentry, Datadog, PD, etc. that offer not only uptime alerts but all kinds of other stuff for a range of budgets.