True regarding the late-comer aspect, although it is less of an issue when using mailing lists with an archive. In the past, when lacking an archive I also just asked another participant to send me the earlier discussion in mbox format, which was easily accomplished with the unix MUAs of the time.
Regarding the actual modes of discussion I was thinking of though, usenet and email are mostly the same.
> I was thinking of though, usenet and email are mostly the same.
For the most part, they are and many readers support both protocols (or at least they did in the past). The nice thing about NNTP is that it doesn't require maintaining a separate archive or having someone send you an mbox file to import. Just subscribing to the appropriate groups was sufficient (depending on the article retention policy).
Regarding the actual modes of discussion I was thinking of though, usenet and email are mostly the same.