Earlier quoted context omitted.
Comprehending why the Twitter limit exists should let you comprehend why there's no point for App.net to follow it. The service won't actually be used for "micro-blogging" unless users are constrained by some limit, but 144 is too damn small. Nobody would ever have picked it if they weren't forced to, and these days they aren't. What infinitesimal fraction of modern Twitter users in App.net's target market do you ima…
I've been using Tent ( https://tent.io ) which also adopted 256 characters, and I think it's actually quite generous for statuses. Maybe too much; the nature of microblogging changes when you don't have to be concise. I bet the sweet spot is probably somewhere in 160-200.
If you go beyond 140 it is then no longer a microblog post, but rather just an ordinary blog post.