I had my site switched from Dolphin to UNA and had over 35,000 members but due to accumulating server fees and not having a way to make money on it I could never keep it up and running for more than a couple months at a time. The server I uses accumulates the server fee even if my website is suspended. I think once App development is steady at a nice price there will be plenty of members for everyone because advertising an App is easier than SEO of a regular website even if it's a mobile website. My dream is to have my website as an App but so far it seems like it's out of reach without spending a huge amount of money combined with server fees and maintenance fees. Until app development competition lowers prices my website will strain under monetary fees with no way to recoup the fees. Making money off an App is easy, it's the amount of money to make the actual app that's holding a lot of potential back.