Yup, Twitter and Tumblr and Hubski all have this in common, and as the userbase increases that feeling will increase as well. I didn't even see this post until I clicked the Global tag, which I feel is sorta like the "trending tag" on Twitter -- btw mk, may I ask how Global works? Don't want to give an improper representation. I didn't see the value in Twitter until I started following tags such as technology and gaming and programming, etc. Then I found other people who have my interest, and had my own little Twitter bubble. Referenced it as a cocktail party during a presentation I had.
Global is everything that isn't pulled into your feed by following or shares, excluding anything that you ignore. Globally-ignored users won't be seen there unless you toggle on 'show-global-ignored' in your settings. But, there are few of those, so the experience will be pretty much the same. BTW, I enjoyed the post emcadwaladr. I am purposefully holding off before adding my 2 cents.