Since I lately see technically invalid twt subject hash tags for machine-parsable conversation grouping every now and then, I just taught the twtxt parser of my client to recover these (#1234567) subjects. Now they are grouped back into the proper conversations and do not form new root/single twts. Note, that the offending clients did not expand the hash tag in the subject to a proper (#<hash url>) form prior to publishing the twts. (Let’s see whether my first markdown code will be expanded by twtd to a linked hash tag or not.)