Well, you know the bubble by the burst, before it happens labeling it as such is bound to be speculation.

What I meant with this comment is that steem is one of those cryptocurrencies that have a clearly outlined utility and a bubble might be created when it's easy to get a simple activity overrewarded. $10 rewards for commenting might be just that, but who knows, the current rewards might also be viewed as too high already but they seem to be pretty stable. I guess we'll see how it goes and if STEEM can be stable at $10, that would be awesome for us who have become invested at much lower prices.