There may be slight variations in confidentiality policies between school districts but, in general, we all need to follow federal and state statues on privacy. In short, people outside your classroom should not be able to identify your students in pictures or words and should not have communication access to individual students.
With respect to using social media in your classroom you must check with your administrators who will be well-versed in the school district’s policies regarding what and how you can use it with your students. Most districts will likely have media release forms for families to allow or deny the school permission to post photos, work or names of their children. Don’t assume that all parents are ok with you posting information that can identify their children. Only use social media if you have a plan to use it educationally.
I categorically oppose using private or personal email addresses, Twitter feeds, websites, or Facebook pages to communicate with students or families. Set up specific accounts that are strictly for your classroom(s) to use. There are many web-hosting services that are specifically designed for teachers and classrooms. Check with your district if they have licenses or agreements with specific webhosts for you to use. As much as possible password-enable your websites and control who has access. Inform parents of what and how you are using social media. But, even giving parents access to sections of your site where your students might be engaging or posting work might be problematic. Again, check with your administrators for advice.
I primarily used websites where students would have discussions on topics, post research, upload presentations, find deadlines for assignments, download worksheets or homework and have links to videos and content that I used in class. I often had weekly “What’s this?” or “Who is this?” photos that students had to identify and post facts they had researched.
But you must remember: Keep your students safe. Keep yourself safe.
Hope this helps!