I’d like to make some official rules for experiment suggestions.

• Must be Totally Free to sign up.
• Must be at least one way to use the site that is free and doesn’t require a credit card.
• If it is a money making (or prize earning) site, there must be a way to do it without referrals.
• No Adult Content (ads, etc) on the site.
• The content must be available to US citizens, and mostly in English.

Also to clarify a few questions:

• May be a GPT (Get Paid To) site, but it does not have to involve making money. It could be for instance a site that helps drive users to a website, etc.