That is true, and I actually think the default length may be slightly short even for microblogging in some cases (although I would define a limit in bytes (and perhaps also character cells) instead of characters; if you need multibyte characters then you can probably write what you need in less characters anyways). This is true in other software dealing with twtxt format too, not only twtxt.net.
For full blogs, long notices, full discussions, etc, I think NNTP is much better, so I would continue to use that. But for microblogging, NNTP seems rather excessive to me, so twtxt can be used for microblogging can be good; the format of twtxt is simple and is reasonable and look like good for making a timeline of short messages written by one person (that is what is microblogging anyways, isn't it?).
For full blogs, long notices, full discussions, etc, I think NNTP is much better, so I would continue to use that. But for microblogging, NNTP seems rather excessive to me, so twtxt can be used for microblogging can be good; the format of twtxt is simple and is reasonable and look like good for making a timeline of short messages written by one person (that is what is microblogging anyways, isn't it?).