My favorite social network is the one I have on Goodreads. I love to see what my friends (who are readers) are reading. I also have found a bunch of people whose book tastes are similar to mine. Everyone is interested in the same goal: finding and reading good books.
When someone overshares, or gets soapboxy, or just spammy, I just unfriend. I did this with my sister! That's something I'd never do on Facebook.