Dr. Pepper is a weird soft drink. Legally it isn't a "cola," and instead is apart of the "pepper" category of soft drinks due to its hard to explain and unique taste. Dr. Pepper like Miracle Whip prides itself on its uniqueness in its marketing and branding. However that unique flavor has come at a cost for its distributors (usually Coca Cola) where it just doesn't sell all that well overseas. In Asian market in particular Dr. Pepper isn't that popular meaning that it is a rare beverage to come by in Southeast Asia and only reasonably available in South Korea and Japan. That said it still struggles amidst a great amount of competition in Japan.
So in comes Steins;Gate with a very visible beverage called "DK Pepper!" Oddly enough DK Pepper is NOT a form of product placement. The name "DK Pepper" was purposefully titled that to avoiding copyright infringement suits. Despite this fans of the Steins;Gate games and now the anime are buying the beverage as seen on the Amazon.jp recommend products tab with the connect between the two rather clear:
It's not just Amazon.jp that's seeing this. Kotaku and Japanator are reporting that Dr. Pepper is selling better in Japan thanks to the show. So how do fans of the show feel about this newly discovered beverage? It's good but takes some getting use to.
So where does this place our new anime originally based on an Xbox 360 exclusive text adventure? Oddly enough it is making an impact in markets some never even anticipated.