yes, it relies on an external server. This is an app we built for our selves, it solves a problem we all have had before so we are not thinking about killing it.
Besides, I am thinking about making it open source so people can easily deploy their own version on heroku for free, it's just a couple of commands.
We'll suport reddit once we complete the HN extension, this is our roadmap:
- map HN usernames (so you can find people easily) - import saved links - save link to HN discussion