I did something like you describe this past year with my 12th graders--it did not involve parents. I found Google's Blogger platform easy to use, although students often had trouble posting comments from Macs. Additionally, the teachers were the only ones who had access to post new topics on the blog (so students had to email the initial post to one of us) since allowing access to each student would have been too complicated, but comments were set to allow all commenters.
My setup was a little different than what you describe since it was 12th grade. 4 students were assigned to post each week, each one from a designated section from the Parsha/Haftarah to avoid overlap. They were informed the week before so that they could email me their posts by Sunday to put up. They were required to quote a pasuk and then raise a question. They were invited to use mefarshim but most did not.
Every other student in the grade then commented on one of the 4 posts between Sunday and Thursday. Again, most did not use mefarshim as the questions were designed to engender discussion of personal opinion. My colleague decided to use some of class time on Fridays to read through the posts; if I were doing it again I would adopt that model. I also would consider being a little more strict on what was required to receive credit for a post (i.e. adding something substantial to the discussion), but it would depend on the class.
I'm not saying it worked perfectly. For example, we never had 100% participation on a given week and we had to repeatedly instruct students to type their comments elsewhere, save them, and then copy-paste into Blogger to submit and check that they went through. But overall it was a positive aspect of Tanakh class-- many students enjoyed it and it was a great opportunity for students from different tracks to interact with one another regarding the Parsha.
Feel free to be in touch if you have any further questions!
Chava Lerner
Ma'ayanot Yeshiva HS for Girls
