At the beginning of using MyPortfolio I had the students sign to agree with the following "terms and conditions".

Blog and Myportfolio Netiquette
As a class of bloggers it is critical that we agree on some general guidelines for our blogging. Please read each of the guidelines below. By using MyPortfolio you are agreeing to follow each of the rules.
Keep your details private No personal information should be included anywhere in the blog. As you post, please use your first name followed by your last name initial as a username (ex..catoh).
Conduct : All users should remain respectful – you may not post anything that is rude Content: Stay on topic of the discussion and keep your comments school appropriate. This educational blog is not a place to socialize. Sign your username to any comments you make.
All users should be careful and conscientious about what they write because blogs are a public place. This means that all writing should be respectful as well as grammatically correct. (Because this is an English related blog, please refrain from using text lingo.) Even if you close your account what you have written might have been picked up by someone else and still be out in the ether sphere.
No plagiarism! Please be sure to give credit where credit is due.
Monitoring - Blog editors have the right to delete any comments posted that are inappropriate or off task. Anyone finding something questionable on the website, please notify the blog editors and myself immediately.
Myportfolio is an online classroom – MRGS classroom rules apply – Respect for self and others and the school!
Rules aside I am sure you will find many rewards as we go on this journey together. I see Myportfolio a great place where you can:
· be proud of your work
· work smarter
· work together
As well as keeping a portfolio of your practise essays and other artifacts you can also use Myportfolio to start building up your resume/CV.
Enjoy. J