This article from eSchoolNews does a good job emphasizing some of the relevant lessons from a recent Pew report:
For most media outlets that reported on an important new
survey measuring the impact of technology on teens’ writing skills, the
big news from the survey was that emoticons and text-messaging
abbreviations are creeping into students’ formal writing assignments.
Buried beneath the alarm of writing “purists,” however, was a
promising finding with equally important implications for schools:
Blogging is helping many teens become more prolific writers.