I've been reading this and other online websites, blogs, channels (you name it) since 2000. There has always been a steady flow of JWs out of the organisation. In Scotland there was flurry of exits around 8 years ago. (iCeltic, PasswordProtected, Ninja, HoboKen, and other anonymous members, including many who haven't posted in a long time) I don't think this site in particular is more active now than in the past. Many prominent former JWs have outgrown the community and moved on: in particular AlanF, Narkissos, LitteToe Leolaia and so on. Some have passed on too including Mouthy and Farkel and many more from a pre-Internet generation of leavers.
What has changed dramatically in the last couple of years is the Watchtower organisation itself. It seems the steady drip of leavers has finally caught up with them. Plus JW children are not getting baptised in the same numbers. That combined with their abysmal results from preaching means they are definitely at a turning point. The financial woes on top of everything else are what might cause a sudden collapse, rather than a gentle demise, as some other religions have enjoyed.
Youtube, Facebook and Reddit are also relatively recent developments that I've begun to take an interest in. In total the online ex-JW community probably is much larger and doesn't rely on old style forums so much.
Having viewed developments for so long, I had adopted the common wisdom that things will never change at Watchtower and collapse is not a realistic outcome. The developments of the last couple of years have concivned me otherwise. The organisation has already undergone dramatic changes. What's more these changes do not seem strategic or planned. They are short term measures in response to real financial and organisational difficulties. And in that context it's not unreasonable to wonder whether the measures Watchtower has taken will be enough to avert a serious organisational disintegration of some sort.
So yes I think it is appropriate to talk about a wave of momentum at the moment.