Does everybody trust into these hosted services? (I do not.) How about to run your own one? - http://pipes.deri.org - still alive or dead? - https://github.com/ggaughan/pipe2py - looks alive - http://neyric.github.com/webhookit/docs/index.html - Alpha and dead? - swiftly.org - started as a open source project, but nothing released and dead?

Did I forgot something/somebody?

Just to be complete, GUI as a JS lib: - http://jsplumb.org/jquery/demo.html - http://neyric.github.com/wireit

And additionally two commercial hosted projects: - http://www.wewiredweb.com (based on http://www.mashablelogic.com) - http://tarpipe.com/