reinventing the wheel
Perhaps I misunderstood the core idea of the project, but hasn't embedding-app-session-ID-into-URL been known and widely used for years ? Moreover, using a set of related temporary IDs with exactly one active severly depricates usability of the system, because the user cannot use multi-windows browsing in the scope of a single session.
An open, cross-platform journaling program.
A scientific plotting package.