As a platform, they are big on encouraging people who wouldn't otherwise write to do so, so you get a lot of articles that are by new writers or who lack a presence elsewhere. This is a good thing in general as we need more diversity in people writing and sharing their experiences. It does mean you need to take this context on board as a reader, though.
I have a feeling it's becoming a self-promotion spam platform like Quora.
It's counterproductive. It comes to the point where I do not read anything from certain sites. Diversity is nice, but it does not mean that someone, who has little knowledge in certain area, should write an article from the area.
Only well-known writers have anything to say to the rest of us? Seems like a questionable proposition.
"Only well qualified writers should tackle technical topics in depth" seems like a much more reasonable proposition, and is (I believe) more what mikulas_florek meant.
Well, let me try to clarify what I mean: there is no obvious correlation between having your own platform (or being an experienced writer, for that matter) and being qualified to address technical topics.