Yes I did joined/tried several of those reward based or paid to post social media sites.
I already forgot some of the names of those sites. Some old sites that I have tried that I can remember are Mylot and Mylikes.
Most recent that I have tried are Whaleshares, Trybe and Weku. I am not active on the first two sites. In Weku, I have been quite active and just waiting if the site will really be a legit one or a scam.
So far, Steemit is the best reward based social media site that I have tried. I have learned a lot especially about cryptocurrencies. I am also confident enough that Steemit will still be on the net for more years to come.