This is completely the opposite of my (also a millennial) experience. I blog on a regular basis, post things on Facebook, LinkedIn, Twitter, what have you. The amount of thought that goes into each post ("could this be misconstrued by an employer?" "if I post this, will it offend one of my friends?" "Could this retweet become viral?") is paralyzing and exhausting, but not sharing is just as hard.
I've written a post about this feeling [1], but I don't have any solution. As someone who enjoys sharing ideas through writing and meeting people online, but is also very aware of how mob-happy our online civic society has become, it is a hard position to be in.
[1] http://blog.vickiboykis.com/2014/01/the-snarling-crowd-in-th...