@neil As you say in your blog, as drafted this goes far wider than social media. For those not familar with the OSA, on my reckoning it could include:
• Wikis
• Video sharing sites
• Video conferencing apps
• Messaging apps
• Shareable file storage
• Blogs, newspapers and podcasts with reply to comments functionality enabled
• Charity-operated support forums
• Sports club forums
• Hobby forums
• Neighbourhood news forums
• Online games
• Review sites (e.g. movies, travel)
• Music sharing sites