That would be totally amazing. I played with the idea of letting clients run custom code on my servers but that didn't materialize so far due to the amount of w

That would be totally amazing. I played with the idea of letting clients run custom code on my servers but that didn't materialize so far due to the amount of work required to safely allow that. Being able to do that easily would certainly make online tools more configurable for power-users - or let an application-economy flourish where users can share small snippets that customizes a service in given ways. For reference, I run a website analyzing service that crawls websites every week or so and reports errors, mainly broken links. As all the document sources are available at TCP level it would be trivial to extend it with custom error reporting.