Channels are consistently the most popular part of Aertv. It's the core of the service, part of what makes it unique and also the oldest part. It should be obvious then why Channels live on the homepage of the site.
I inherited the design and stewardship of this section when I joined the team in 2011. Since then it has gone through a number of iterations, some cosmetic, many under-the-hood but the biggest visual change happened when I redesigned the section in early 2012 with a brand new responsive design which made it a lot easier to use on mobile devices.
Part of this job was to make the video player responsive. This involved some clever CSS trickery in the form of intrinsic ratios for the Flash mode and then using the Brightcove Player API to pass width and height values to the player, telling it to resize, when in HTML5 mode.
One of the big challenges with Aertv was performance and scaling to meet capacity. From early on we've tried to optimise as much of the site as we can. For instance, when I worked on the tabbed feed widget in the sidebar I built it so only the active tab rendered on page load. The other two tabs only load their content if the user interacts with them.
One of the trickiest parts of the design was to make it responsive but also allow for fixed size display ads. At that time people weren't even thinking about responsive ads. My solution was to only call and render certain display ads (such as the wallpaper and leaderboard) if the viewport is big enough. If there was enough room then we'd asynchronously load the ads. We had to made other design considerations such as restricting the maximum width of the content to leave room for a wallpaper/skin ad unit.