I always liked apps that display posts from social networks in multiple columns like Tweetdeck, so I made one for Steem. The working title of the app is “Columns for Steem”, haven't really thought much about a name for it yet.
It’s a website right now, but I could turn it into a Desktop app for Windows/Mac/Linux using Electron at some point if people prefer that. You can check it out here.
You can open as many columns as you like, their width changes as you add more and if they get too narrow a scrollbar appears at the bottom to scroll sideways. On a 1900x1200 display, five columns works best without having to scroll sideways, just experiment to see what works best for you.
When you click the ADD COLUMN button in the top right corner, a dialog window opens where you can enter either a #hashtag or a 
Columns (with the exception of username columns) can be sorted by either “Trending”, “Hot”, or “New” by clicking on the button in the top left corner of a column. Username columns can only be sorted by “Blog” or “Feed”, which is basically like “New” but “Blog” shows the posts the user created and “Feed” shows the posts the people he follows created (so to show a column with your own Steem feed, just enter your username and change the sort order to Feed).
In columns sorted by “New/Blog/Feed”, new posts scroll in every 60 seconds when the column is scrolled to the very top (you can also click on the header of a column to scroll instantly to the top).
So you can basically open a few columns like #technology, #news, and #bitcoin and have a waterfall of news displayed on your screen where new posts scroll in automatically. For other sort orders that doesn’t make sense, so their content is just replaced completely every 60 seconds with new data from Steem (again, only when the column is scrolled to the very top, so that posts don’t change under your nose while you scroll down a column to see what’s there).
The app has both a light and a dark theme since that is popular nowadays. You can switch between the themes on-the-fly in the settings drawer (click the icon in the top left corner to open it). The design isn’t final yet, might still change, it’s based on Google’s Material Design which you probably already know from Android apps or YouTube for example.
The app tries to use as little bandwidth as possible, but keep in mind that for every column you add more data has to be loaded from Steem every 60 seconds, so you might run into problems on slow internet connections with too many columns. Columns sorted by “New/Blog/Feed” use the least amount of bandwidth, since these columns basically only load new posts whereas for the other sort orders all posts have to be reloaded every 60 seconds.
Columns only show 25 posts right now and don’t load more posts when you scroll a column to the very bottom, I’ll add that in one of the next updates.
I’ve only worked on the app for five days, albeit full time, so see this as a prototype / alpha release for now, there will inevitably be bugs in this very first release and there are still lots of things I’ll add or improve in updates. I’ve tested the app on the latest stable versions of Firefox and Chrome, other browsers might work but are not officially supported for now. Please report any issues you run into and general feedback in the comments. Posts written with some third party Steem clients are displayed without images, I’m working on that so no need to report it.
Right now the app is basically a frontend for Steemit, which means you don’t have to login with your Steem account to use the app, but you can’t read the full post or write or vote on posts within the app itself, instead you can click on a button that brings you to the post on Steemit. If there is enough interest and support for the app, I could turn this into a full alternative to Steemit like Busy or eSteem, so that you can also read, vote on and publish posts using the app.
As far as I’m aware that’s what the Steem creators want since Steemit was only meant as the reference implementation of a Steem backed social network, they want other people to write apps that completely replace Steemit. That’s obviously way beyond the scope of a little hobby application, I’d also have to maintain a server, host images which also means curating them in case something illegal or copyright infringing is uploaded, so not something I can do without funding. But if there is enough interest and therefore upvotes on my Steem posts about it, maybe we can crowdfund this together, doesn’t take that much money. But that’s for the future, for now it’s just a little hobby project I wrote because I wanted to use it myself :)
The app is written in ClojureScript, a Lisp dialect, and uses the Reagent framework which is a minimalistic wrapper on top of React. This allows me to develop the app while it’s running (hot reloading) which is really cool and saves a lot of time, no compile->run loop. I’ve got another Steem project using the same technology called Steem Observatory, basically a little dashboard for Steem which shows you analytics for your Steem account, and I’ve also written a few articles about the technology on Steem, including a tutorial. To contact the Steem API, I use the dsteem library, it’s like Steem-JS but written in TypeScript. Since there is very little developer documentation right now for Steem the types help a lot in figuring out how the Steem API works.