Read this post from instapundit.com on students who text message in class. Be sure to follow the link there to the Ann Althouse blog. Briefly, they -- like me -- think that since WiFi makes messaging inevitable it's best to encourge the most beneficial use of it. And as I've discovered this term, blogging your course is a dream for the instructor. (The instapundit post includes a link on this topic to PrawfsBlog.)
For my part, students text messaging to each when they miss a point or don't get someting is advantageous and unobtrusive. And the fact that students can google during lecture will allow them to bust profs who bend the truth for ideology and will -- hopefully -- embolden students to raise objections.