Be nice. Or else.
Tobias van Schneider's, of course. http://vanschneider.tumblr.com/
Muting is my favourite feature. You can choose to mute by user, hashtag, client they post from (so you can block Facebook reposts for example) and for whatever time frame you choose it from. I like to use this to mute hashtags for a show I haven't seen yet (I'll mute #gameofthrones until ...
Same reason you use Designer News: keep up to date, find interesting content, meet people in your industry or area. It's really what you make of it.
They kill it every time. Saw Jason Little speak recently and he really gets it. Excited to see what happens with For The People!
Yeah I used to work in this exact setup. I used Sketch Measure to detail the design with specs. Then provided icons etc. as needed. In the end the developer was happy to measure it out himself, so all that was needed was font stylings. Good luck!