Communities are great. But I love the collections even more. My followers can follow the collections they are interested in. This allows me to have multiple interests and create multiple feeds for my followers to choose from.

The best part is that it could be created here on steem simply by a front end update. The blog tab for a user on steemit could list all the tags used by the user. And by selecting a tag you would get all posts with this tag for the user. Everything else would get filtered out. It would be identical to collections in G+

And the feed on steemit could get updated to display new posts using a combination of "user"+"tag". You would follow a set of tags from a user. Or "user" if you want to get all new posts from this user into your feed (like it is today)