gets an A. In fact, besides the character limit, perfect linearity has always been one of 's most appealing features. Someone posts a tweet, and it shows up at the top.

in a browser also gets an A. The company offers a Twitter-like stream of perfect linearity. In fact, they even got a lot of flak from the nerdy techie segment of their audience for not filling up all the white space on the interface. It's interesting to note that a failed precursor to +, called Google Wave, suffered from a two-stream layout, which was awful and contributed to its failure. The phone app for Google+ is also very linear. (The tablet app, not so much.)

gets a B+. They have a single, linear stream, for the most part, but every few items they'll slot two items in side-by-side. It's not a visual disaster, but it does represent the primacy of being "different" over user appeal.