Sorry for so many posts in a row, but just one more thing to point out if it is not clear: Whitelisted people can point you to posts to download, but you can still download posts made by people who you have not whitelisted, provided a whitelisted person points you to the post. People who are not whitelisted cannot point you to posts, and this means the only way you can see their posts is if somebody you have whitelisted points you to them. But after you are pointed to the post of someone you have not whitelisted and you obtain it, you can whitelist that person directly from the post by clicking a button. If they also whitelist you, then you can point each other to messages, and easily communicate with each other. If somebody points you to spam, you can just remove them from your whitelist.