The whole equation boils down to this: Will this new account gain me enough exposure to new people to justify maintaining (yet another) account there, on top of FA? Or are most of the people there also on FA, and I'm simply, for the most part, showing my work to the same people twice?
On top of Fur Affinity, I maintain Deviant Art and Tumblr accounts. Tumblr follows my submission releases from FA pretty straightforwardly, though I often release sketches and in-progress works on Tumblr that I don't let out anywhere else. Aside from a submission blog, it's also taken over the role of my on-site sketch blog. Foremost, Tumblr also gives me possible exposure to non-furries and others without FA accounts. Deviant Art is largely the same. They have greater restrictions on erotic pieces, but the trade off is the exposure to non-furries. I've received more than a handful of comments and notes on DA from people who express their unease about furries but who enjoy many of the pieces I submit there. In the instances of DA and Tumblr, it's worth it to maintain accounts.
Inkbunny was a site that almost had it. They have a great interface and they had the thing that could have really turned them into a valuable site for popular artists: a straightforward commercial system where the artists could offer additional portfolios and comics for fans who liked their work enough to support it with money. It's basically the business model I have for my website, and have been making a living off of for years, now. It provided the incentive: If you're a popular artist, you now have a reason to maintain both an FA and an IB account. Sure, the site was started by some people who supported and produced some questionable and creepy material (publications which sexualized cartoon children), but the site didn't have to be about that if it drew enough traffic and accounts to make it a commercialized (read: financially profitable, growing, dynamic, outstanding) version of FA. The creepiness would have been a side-show, buried amid popular names and images offered by a host of artists inspired by making side money and producing more material than they would on FA for free. There would suddenly be a good reason for heavy hitting artists and their fans to go to IB, even as they maintained accounts on FA. When faced with their transaction service issuing an ultimatum, they chose to scrap the commercial system in favor of being able to host pictures of naked and sexualized cartoon children. Sure, they had the right, but the decision destroyed any real motivation from busy and popular artists to maintain an account in both places (unless they wanted to draw naked furry children). The decision took away the one thing they offered to people that made their site something more than just another FA.
I think before someone just thinks "let's make a BETTER art hosting site than FA!" they should really work on addressing these realities, looking at such sites from the standpoint of what makes them attractive to both artists and fans, beyond just little features, chatrooms, and slicker interfaces. The only thing FA has going for it is the sheer volume of traffic available, largely by inertia. Instead of just making a site that hopes to draw that traffic, give artists a reason to tell their fans to check out their gallery on your site, instead of FA. Give them a real incentive.
This isn't to say I don't dig how a lot of those other sites look. It's not to say I don't wish they'd become the dominant community art site. I think offering commercial options beyond donation buttons is the key. That being said, I may check out SoFurry's stuff in the future and see how I like it, but it doesn't look like it'd be a regular draw.
Just my thoughts on the matter. This isn't meant as a big smear or bitch toward anyone who chooses to run their sites a certain way. It's something I've talked over with a few other artists and have mulled about in my mind for a while now, so I thought I'd fill this journal space with it.