It allows you to actually design the characters in your strip through a very well-designed “mix-and-match” feature. In addition, you can “reply” to other people’s comics with a comic of your own — now that would make for an interesting comments section!
The site hasn’t “officially” launched yet, though you can sign-up and start using it now.
There do not appear to be inappropriate comics on the site, but it’s unclear to me if the site’s owners will be carefully monitoring what’s posted. It would also be great if they included some way to moderate responses before they’re shown.
Until those two issues get clarified, though, the site, as great as it is, may be more appropriate for adult ESL classes rather than K-12 ones.
Writing comic strips are just one more vehicle that allows English Language Learners to more easily develop writing skills.
I have links to many other “create a comic strip” sites on my Examples of Student Work page under Student Comic Strips. The ones listed may not provide the same features as Toonlet, but, for now, they also have a few more safety advantages.
All these sites, as well as Toonlet, allow you to post the url address of your comic strip on a blog or online journal.