I like seeing these different ways of using the underlying Steem database.

I have a few notes.

It seems that the Screem UI is only paying attention to whether the post has the #screem tag and not whether it has the "screem" value in the "used-by" field of the post's JSON metadata. For example, the post that I am replying to is included in the Screem feed (using its title as the content of the "tweet") even though it doesn't have the "used-by" field in it is JSON metadata. Steemit users may wish to tag their long-form posts with #screem to discuss the Screem platform, but may not wish for their post to show up as if it was a "tweet" (what are you calling it instead, a "screem"?) in the Screem feed. So I think it makes more sense to just filter based on the "used-by" field you already create using your UI.

Using posts for micro-blogging is not the best idea since the change to Steem which put a soft limit on the number of posts in a day before a penalty is added to post rewards. Every tweet/screem people create using Screem will eat up into their quota and lower their potential payouts on the long-form posts they create on Steemit. What I would like to see instead is for Screem to utilize comments for its tweets/screems so that users can micro-blog as much as they want without hurting their post payout rewards. However because there is a time limit of 31 to 44 days after the top-level parent post of a discussion is created before no new comments (or at least the regular type that can earn money) can be posted on that discussion thread, your platform would have to be a little clever with how it manages the comments and discussion threads. It would essentially need to create a new post for the author once a month so that it always has a recent designated discussion thread in which to post new comments by the author that act as their tweets/screems.

Other ideas for future improvements include using the JSON metadata to refer to another comment that is also acting as a tweet/screem, in either a way that acts similar to a retweet on Twitter or in a different way that acts similar to embedding a tweet on Twitter. The Screem UI could then enable similar features (rescreeming and embedding screems) and represent them appropriately by taking advantage of the appropriate JSON metadata.

Finally, I noticed that the time displayed on the tweet/screem in your UI uses the last edit time rather than the creation time. Was that a deliberate decision? I think it would be nicer to show the creation time but also include in parentheses the last time it was edited (if it even was ever edited).