I hope you realize that you are exaggerating. Out of all of those, the only one that an employer has ever had any interest in was my GitHub account and I have gotten software dev jobs before I even had one
Of course i'm exaggerating, I've worked in software for 10 years and never had any of those. Until about 3 months ago I didn't have a twitter account. I've never been out of work.
BUT, the amount of people that look at me funny because I didn't, and the article that i linked to just reinforces that.
I can't wait for a service to pop up where for $500 they will make you an amazing, sterling Facebook account you can "share" with people. It will be populated with believable postings from other people you know, yet all of these other people will be cardboard cut-outs.
My cousin and I came up with a similar idea; we called it Fakebook, and then promptly went on to forget about it. There's gold in them there hills, though!