Diaspora still lacks punch because proper implementation (i.e. as a personal web server, not joindiaspora.com et al.) is still for the wizards. But the beauty is, that when (if? (vaporware?)) it is properly implemented, it will differentiate itself from GooglePlus and Facebook in a way that offers value to mass market consumers in the form of privacy and data portability. If consumers could buy an easy-to-install, pre-configured wall-wart running FreedomBox/Diaspora with the option of gratis/paid services for specialized configuration or feature development, some would be willing and able to buy such a device.
Unfortunately, the issues around privacy and data portability/access are not issues that typically capture the mass market’s attention. Will enough users care to expend the energy to create an instance of their social life on Diaspora and learn its interface? I’m skeptical, but if Diaspora keeps developing like it is, I see no reason to leave. For me personally, Diaspora has been like Twitter on steroids. My “use” of Twitter has pretty much been reduced to my Diaspora posts being pushed out to Twitter automatically.
Putting aside social pull and the goal of market power, I think the success of Diaspora should be measured similarly to the goals of the GNU Project. While advocates of software like the GNU/Linux operating system enjoy hearing news of market success, they see the existence of free software itself as the most important success, rather than growing popularity. Maybe there will only ever be enough capital behind Diaspora to sustain a niche market or perhaps, it will come to the mass market. Regardless of that, even if a small network of users exist who can run their own privacy-aware, free personal web server, that’s a success too.