Yes, comments!
I should probably be doing other things, but today I decided to see what it would take to activate a commeting system. So - I tracked down an excellent post by Miek Gieben, http://archive.miek.nl/blog/archives/2009/01/26/nanoblogger_comments_update/index.html, who created a simple php and database-less comment system for Nanoblogger in 2009.
Miek's system worked painlessly in my exploration. I decided to remove the support for a posted web site URL. Odd people and robots seem to have a high propensity for spamming sites with links to other sites. This was a quick commenting exercise. The other thing that I needed to take onboard was that incoming bare dollars php needed to be backslashed to survive the text processing in Nanoblogger, but that was very simple to achieve.
I plan to leave the comments switched on for the permanent archive pages in Nanoblogger and see if there is any interest - or spamming - and then I'll decide what to do next.
In the meantime, thank you Miek!