Yahoo Pipes are a very intriguing choice for sort of a poor-man's server-free ETL solution, but would it be a good idea to build an application around one or many Pipes? I've really only used them for toy things here and there, with the only thing I've used longer than a week or two being one amalgamated and filtered RSS feed that I've plugged into Google Reader (which has worked great, but if it goes out for a while I wouldn't notice).

So, my question is, would building an application around Yahoo Pipes be reliable (available most of the time)? Ideally it'd be something I could rely on being up 99+% of the time.

It looks like the Pipes Terms of Use permit building apps around it, but I am unfamiliar with anyone building anything significant using them.