A generalised notification system
Short, concise description of the idea
Funnel all of the things that LJ can notify you of through a single point that can be accessed via email, the web or a client app.
Full description of the idea
Currently there are a variety of different kinds of notifications that a user may receive including email notifications for responses for comments and invitations to communities on LJ itself and the fact that there are new items available on their friends list via a client program.
The streamlining of all of these into a single notifications system, whereby not only are all notifications available via a single web page, but other kinds of notifications can be subscribed to would make the system much more flexible. Ideally one single system should allow the user to be notified either via email, web or an LJ client.
Once the basic system is in place, it could then be extended to allow subscription to all comments on a post, or to posts on specific journals that are low traffic and might otherwise get missed. For instance, I might wish to be notified whenever the status journal is updated, or whenever there's a paid_users post.
There will, admittedly be an overhead on this, especially if people's subscriptions run wild, but it might, in fact, save on bandwidth if it means that LJ clients checking for updated friends pages can do so more efficiently. For large threads that are updated frequently (for instance, many news posts) it would probably be wise to batch numerous updates together into a general notification that 'many posts have occurred'.
An ordered list of benefits
An ordered list of problems/issues involved
An organized list, or a few short paragraphs detailing suggestions for implementation