One of the the major developments with SB Nation United was that sites across the network were optimized for use across all mobile platforms, which made the apps rolled out last year obsolete.
From SBN's Nebraska site Corn Nation:
Speaking of mobile, the SB Nation application is not being supported any more. If you have the Android or iOS app, you may as well get rid of it. (The reason is it doesn’t make sense for them to develop five different applications for each ecosystem out there to interact with a website when a single HTML5 website can dynamically respond to the device resolution.)
Eric Eldon of Tech Crunch has more about SB Nation's new mobile functionality.
The more subtle but still significant upgrade today is about making the same product work across any device. The text, images, and even ads are responsive to screen size. If you open any of your sites on your phone or your tablet, each piece of media will automatically adjust (try resizing your browser on any Vox site to see for yourself). The multi-pane "cover" display will move images down from a big box to a long-thin column. Text will move down into new lines instead of getting cut off. Background wallpaper ads will shrink down and collapse. Tech-wise, this last set of features is just HTML5 and CSS. The difference is that the product looks great for readers, and doesn't ruin the ads.
If you're having problems accessing this or any other site in the network on your mobile device, please contact firstname.lastname@example.org or contact them via Twitter @SBNSupport.
If you have ideas about how we can improve the mobile experience just in how we organize content on the site (e.g. where things are placed on game days, where game threads are, what we privilege), leave your thoughts in the comments. Just as the excerpt above alludes to, it's hard to know what that experience is on every device so your feedback is valuable.