Comment 6 for bug 547333

With this patch, wall posts now generate notifications. Specifically:

1. There is a new notification type called "Wall post", which defaults to "Email".
2. When a user makes a post on another user's wall, it generates a "Wall post" notification to the wall owner, containing the body of the message and a link to the user's wall page.
3. This notification is generated both for public wall posts and private wall posts.
4. No notification is generated when a user posts on their own wall.
5. The "Wall post" notification type has been added to the default "Inbox" block on the default user profile page template.
6. Existing user profile pages that still have an unmodified copy of the default "Inbox" block, have been updated to also include the "Wall post" notification type.

One noteable limitation, is that *only* the wall owner receives notifications. So, if a wall owner replies to a second user's comment on the owner's wall, the second user does NOT receive a notification. This will make it difficult to hold a conversation on a wall post, and I expect it's a feature that will soon be requested since that's how comment notifications now work.

However, it'll be tricky to implement non-wall-owner notifications. With comment notifications we worked around it by using the existing page watchlist to "Subscribe" commenters so they receive further notifications. Profile pages cannot be added to the watchlist, however. I suppose we could just change this so that profile pages *can* be watched. Either that, or implement some kind of notification subscription mechanism, and start using that with wall posts.