So I've been working on merging Julianfarr 's changes in, and one issue so far.
Once we've done an initial run, Julian's method simply increments the playcount by plays it finds on last.fm since the most recent run.
However, if you are scrobbling your plays from MM itself (vs just from a mobile device) then these plays will get added twice.
Do people mind this? I'm assuming yes, and as such I cannot merge these changes in without caching the results from last.fm somewhere still which is a big job... sorry folks!
If people don't mind, I'll release a packaged version with his changes - but will probably give the addon a different name, as the end result isn't actually the same.
I am also having a go at writing this script in python - there's already a last.fm api and I'm most of the way done already to an equivalent of the version 3 beta - but it would require people to install python and pywin32 - http://sourceforge.net/projects/pywin32/
so it's no longer as simple as just installing the MMIP.
The nice thing about writing it in python is we get a storage mechanism much easier - and future maintenance would be much easier for me