I'm very much liking the way both @steempress and @threespeak are going after the comment crowds around popular creators. I think back to how many great communities I was in around blogs and old forums which slowly died a death as Facebook sucked the oxygen out of the rooms.
As soon as I feel Steempress is solid enough, I'm going to be putting it forward to a pretty significant site in the UK.
There is no doubt some of the applications are positioning themselves very well for future liftoff. I think you can add D.tube to the list as a feeder system them. The project team there is opening up sign ups to all now which could see a percentage end up with Steem accounts.
It is interesting to watch the convergence of it all.