Homescreen is a new app from Betaworks that makes it easier to post your home screen to twitter. That's about it.
I would love to go on about how innovative this is or how much better a tool this is to share your personal home screens, but I don't think it is. The app itself is simply a glorified share sheet that posts your home screen to Twitter. It has a nice, clean UI, but it's nothing to write home about.
On the web side there is a little more. The best part of the site is that every user gets a personalized page where they can show off their home screen. Mine is here. From this page you can hover over app icons to see a description of them, and a link to see them in the App Store. This page is pretty cleaver, and is a nice, easy way for people to share their home screen with little effort in explaining what everything does.
There is also a Top Apps page where they show a concept home screen with the 24 most popular apps people had on their home screens in the past week. This sounds like a really cool way to find new apps, but so far this is just a list of the most popular apps that everyone has heard of. I hope they add some sort of "trending apps" page like this so up and coming apps have a chance to be featured even if they aren't as common as Twitter or Facebook.
In the end, Homescreen is a well-made app that does something that some people will find useful, but isn't for me. If you want to share what's on your home screen without doing all the work that goes into documenting everything yourself, Homescreen might scratch that itch.