Looking at the note table, I realized it looks A LOT like the standard Joomla content table. Should I have used that one as a content store? After all, the content offers two locations for the message (intro and fulltext) and all the other goodies (except for last access time).
In the end, I decided against it. Creating a new table is cheap, and putting stuff in content means I have to version PSC at the same time as Joomla versions its content store. Better to leave things as they are, and create a separate table.