The most important question that needs to be answered is whats the minimum withdrawal amount because if its 1 Bitcoin and you are paying a satoshi for each post that is going to take a very long time for someone to be able to withdraw and would not be worth it to most people. What do you do if your site is forced to close in a couple of months time do you keep the money because its below the minimum withdrawal or do you pay your customers anyway?
You are going to need a SEO specialist and someone who has connections on forums because going against the giants of Facebook who have top rank on most search engines is not going to be easy to beat.
You did not answer the question on where the money would be coming from to pay users? The only thing I have seen before is sites similar to this, where you are bombarded with advertisements and people do not like it when they are visiting sites with loads of advertisements.
Also, will you be rewarding people for Copyrighted content too? This will get your site closed down very soon, if that happens. You will obviously have to use external storage, because it will not be viable or cost effective to host the content.
Good luck with the site, I am curious to know if this one would succeed or not.
I do not think advertisements are a big problem because if you take Facebook there are a lot of advertisements crammed everywhere and you probably have 3 advertisements on your screen at all times. Copyrighted content would only get the site blacklisted from search engines and if the OP were to receive a DMCA take-down they would just have to remove the copyrighted content. People post lots of copyrighted stuff on Facebook.
I agree on this, marketing stuff is what will get you where you want to go, another one is referral base these two can attract more users to your platform,it's about time we have a big social networking for the Crypto community, we have a lot but it is still cannot get into competition with the big one which is Facebook.
Paying with crypto is their marketing they are already paying directly to customers to get them to use their social media in promise for coins. It will probably take months to get anything worth while and at that point the site has earned probably double the amount from advertisements.