Ello is an interesting new microblogging system with a quirky user interface that a lot of tech insiders have joined and are using. It looks like it's going to gain critical mass, that is develop a community that comes back for news and to post their own short ads (that's how I see most of the traffic on the social networks).
It is a silo. There is no API for posting from external editors, and no way to get content out of it. They do say that the latter is on their roadmap.
They have said they'll never use ads, however it's not clear whether or not they will sell users' info to advertisers, which would make it part of the Internet advertising system. An example, you're discussing motels in Palo Alto on Ello and start seeing ads for motels in Palo Alto on other sites.
The fact that they don't display ads is a minor consideration, in fact it would be more transparent if they did. I had a similar concern for wordpress.com. They were putting ads on blogs for people reading sites, but the authors didn't see the ads. I think they fixed this, and now if there are ads on the site, everyone sees them, so no one is misled into thinking a site is ad-free.
In a Facebook post earlier today I declared a moratorium on the debate as to whether Ello kills Facebook.
I am @d1 on Ello.