Cool stuff. I'm building my own bookmarking service right now with a similar feature set. It supports tags, groups, search.

I've thought a lot about offering it as a service, but I've decided against it for now for a few reasons:

- Pinboard already exists and is super cheap with a ton of features.

- I don't actually want to scale the service to support other users.

- I don't actually want to handle maintenance/support for other users.

- By limiting it to only myself, I can make it work exactly like I want it to and keep the cost really low.