I can't see Steemit as a competitor to Facebook, like Google+ tried to be. This is a strength, as you don't need to get your friends on Steemit for it to be fun to use. However, it's even better for you, your friends and Steemit that those who are interested in a platform like Steemit can find their way here.

However, UI is truly a challenge. I dislike strong communities, but even very narrow groups or tags can work very well. You could have larger groups and sub-groups and still use all of these in your posts. Like about food. You could have food, subgroup of baking, and then subgroups for.. cakes, bread or something similar?
Now even when going through content under one tag I get easily lost and can't find anything specific. It's easy to miss a lot of interesting content.