The RSS summaries are new in 15.5. They are available retroactively if you just rebuild the index, which I have now done for LSTOWN-L. You can configure RSS abstracts globally and override on a per-list basis. You can also specify an explicit RSS abstract inside your posting using a special tag.

The P= values generated automatically by the web interface are the fastest way to access an article, but they will change whenever the index is rebuilt, or more specifically, whenever the contents of the index change as a result of a rebuild, which is the case if you rebuild with RSS abstracts after installing 15.5, or if you change the RSS abstract parameters and rebuild (but not if you rebuild after accidentally deleting the index). This type of link was designed to minimize I/O for a particular browsing session, there was no persistence requirement.

There is a little-known and marginally slower way to access an article that does work across index rebuilds, but there is no way for a template to figure out the necessary P= value (we would have to add support for that). Unfortunately, these links do not survive the deletion of a posting. The problem is that archived postings do not have a unique ID. The closest you can come is date + poster, which in practice is unique for a list with human posters (as opposed to alert scripts or the like). I need to think about this some more, but with date and poster (which WA does have), it should be possible to craft a slower but persistent link that will work as long as you do not delete the message.

  Eric