Is Silo Structure Still Viable?

I read an article last week and someone in the comments mentioned that his website never fluctuates due to Google's algorithim changes. He said he believes it's his tight Silo structure that helps him out.

I didn't know what the heck that was, but I've been doing some research and it seems like veteran internet marketers practice this, but it still seems really strong because authority websites are doing this.

Please, chime in, and if you implement silo structures, please share how difficult, or easy, it is for you.