It's a mailbox-style reader for Twitter.
It's also an outliner, so you can organize the tweets you read into any kind of list you like, including structure (lists within lists).
It's going to hook into Fargo, which is a powerful web CMS, among other things. This means it will be possible to publish tweets on web pages with flexibility never-before attainable. And we'll do this being faithful to Twitter's guidelines for publishing tweets. You'll probably want to use this tool in your work.
Here's a screen shot of Happy Friends in action.
Here's a narrative of how the product came to be.
Here's a getting started doc.
Here's a video that shows how it works.
If you have questions, my email address is firstname.lastname@example.org.
I hope you like Happy Friends!