If you raise Series E it means either you are doing extremely well or your business is drowning and you need a lifesaver. A business that is doing really well typically raises much more than 85M, so I'm going to go with the latter option. In which case, also, an 85M lifeline at this stage means you are not worth that much alive ...
IMO I can see in a very clear way the downfall of SO happened, they undermined the community that made them rise in the first place. Their most valuable asset IS the community, way more than the knowledge base they have accrued. People no longer feel comfortable going there. I wouldn't be surprised if their MAU is going down.
Too bad for Atwood which I think is responsible for the culture that SO initially had, and which lured many of us to contribute. Since he left, it's hard to put it in words but something changed. I don't think he's happy with how the site turned out to be down the road.
tl;dr; what this series E means is that SO will become the new experts-exchange sooner than later.