Blogs aren't dead - the way people share and communicate with readers of blogs is just expanding. You aren't going to write your blog post on Twitter or Facebook - you are going to share the link there to increase the numbers of people coming to your site. Medium is the only thing that is starting to shift this a bit - their entire concept is based around giving people a place to write blog posts without actually having a blog. There are some people and sites that are solely posting to Medium, but a majority are people who are posting to both their blog and Medium, often with links to said blog on the Medium page. Finding and discovering content is just easier now because it is based around what other's suggest is good. This is a result of having too much information and too much stuff to do. Now I need to have some sort of promise that the article or blog or whatever is going to be somewhat good or enlightening in order to read it. When I there are millions of articles and blogs and bits being posted each day, I want to see the best of it. I personally don't trust Twitter or Facebook for that - I trust Hubski or Reddit or HackerNews. Interestingly, I still use my RSS feed that I've been adding to for 6 years now. When Google Reader died I switched to Feedly, which I love. They have a section of the top 3 most shared/liked stories at the top of the feed. It's pretty cool and gives me the ability to easily access the best, directly from my RSS.
Most the blogs I follow have a twitter presence now. Instead doing the blog check and finding nothing new or nothing I'm interested in or not checking and missing content I see it come up on twitter and click through if it's something I might be interested in. So absolutely the blog isn't dead and many blogs are getting a little lift from the social media this guy suggests is pushing them to the periphery.
I do much the same with my twitter, and for those who don't use twitter I use Newsblur as a nice RSS reader.Instead doing the blog check and finding nothing new or nothing I'm interested in or not checking and missing content I see it come up on twitter and click through if it's something I might be interested in.