RE: What went wrong for Tsū - any lessons to be learnt for steemit?
All of this has happened before, and all of this will happen again!
I can't remember Tsu but this does not surprise me at all.
Similarly, there are projects in the works like Basic Attention Token or other advertisement-watching-rewarding projects - ... and these have been attempted before as well in the old early days of the internet (pre-2000). I remember having a program installed on my pc that paid me in (digitized) fiat for watching ads (or rather, run the program that showed ads). Those failed too.
What lessons we can learn from it? I'm not sure.. Maybe don't put too much faith in projects like this? If it sounds too good to be true, maybe it is? Or perhaps the idea is good, but the technology wasn't there yet in the past? Who knows.. This is why diversifying your funds is a smart idea.
Edit: Resteeming, this is a good topic
You went full BSG there
I know, I love that series :)
Yes, things come and things go. If we can learn a little more each time the bus comes round then we can progress.
And, as you say, always have more than one basket for your eggs.