I know several people have commented on my blog post and I regularly direct people to it from Stack Overflow. The plugin is the most visited page on my blog, but I only installed analytics a couple of weeks ago so there's not really enough data to say anything solid.
Telling people doesn't ''always'' work, though; there are a lot of confused individuals out there promoting events like ''keyup'' for input counters and the like. Most jQuery plugins detecting input use ''keydown'', ''keypress'' or ''keyup'' too. ''input'' would serve them much better, catching cutting, pasting, dropping, spell checker corrections and others. IMO, having the event supported by jQuery would immediately increase awareness of the event, improving the quality of input detection scripts around the web.
As for delegation, it would work for the browsers that support the event natively, since it bubbles but, as for the older browsers (namely IE6-8), it would be difficult to get the event working for "future elements". I did think about this to some extent, though, and may be able to come up with a solution based on ''focusin'' or ''mouseover'' -- when an input element receives either event it is checked against the delegate selector and then the ''input'' event is applied to the element if necessary.