i have asked the devs team on telegram and they said they dont pay for dividends
That is right. There will be no dividends, but there will be rewards for social activity, etc.
that's fine, but what exactly does that mean? Is it per post? per likes like steemit?
I think you get rewarded if you share your social activity. It's not your likes they're interested in, but your general patterns of behavior in social networks, what you like in general, which topics, channels, pages and stuff like that. Nowdays, social networks like Facebook gather this information without our knowledge and make huge money on it. With Sphere, we should be in control.
Probably rewards gonna be fixed like a certain amount of tokens for a certain amount of activity, don't know exactly what the measurement unit will be.
The token represent a share of the project. Its not a mandatory for sphere to has a use case for the token. I think the value will come from the value and the utility of the platform. 