http://two.sentenc.es/ conveys a similar idea but did so long before this story, and more succinctly:
"Treat all email responses like SMS text messages, using a set number of letters per response. Since it’s too hard to count letters, we count sentences instead."
"Treat all email responses like SMS text messages, using a set number of letters per response. Since it’s too hard to count letters, we count sentences instead."