BSkyB is an investor in Roku, and the box is built on Roku’s technology. Roku is a lot more expensive than Now TV, though, with a box starting at £49.99 in the U.K.

The Now TV box’s content offerings are also more limited than Roku’s. To start, the box offers access to the BBC’s iPlayer, the BBC News app, Channel 5′s VOD service Demand 5, Sky News, Spotify, Facebook and Flickr. Viewers can also buy a subscription to the streaming service Sky Movies (£8.99 a month for the first three months, then £15 a month) or a day pass to Sky Sports (£9.99 for 24 hours). Sky says it will add more offerings to Now TV over time.

BSkyB earnings: More households connecting their TVs to broadband

BSkyB also released its annual earnings report Friday. In the report, the company notes that “more than 2.7 million customers, one quarter of our TV base, have now connected their Sky+HD boxes to broadband, a rise of 170 percent on last year….meanwhile, our mobile video service Sky Go continues to perform well with quarterly users up 19% to 3.3 million, 166,000 of whom are now paying £5 a month for our new subscription service Sky Go Extra.” (Sky Go Extra lets users download movies for offline viewing on smartphones and laptops.)

Moving forward, the company said, “we will step up the roll-out of connected boxes across our base by offering a low-cost wireless connector to customers that have a Sky+HD box but haven’t yet connected it to broadband. We will also launch a new WiFi-enabled Sky+HD box as standard from September, rolling it out to targeted groups of customers who don’t yet have Sky+HD boxes.”

Sky Go Extra is £5 (USD $7.93) per month for existing Sky customers and builds on Sky Go, the company’s on-demand service for mobile and connected devices (which is free to subscribers). Customers who sign up for Sky Go Extra can also watch on-demand streaming video on four devices, up from the two allowed under Sky Go.

The offerings available to Sky Go Extra users depend on their underlying Sky TV package. Customers who already pay for the Sky Movies pack can “download blockbuster releases around six months after they have ended their run in cinemas,” according to the release. That includes movies like Avengers Assemble and Sherlock Holmes: Game of Shadows, as well as all the James Bond films. Customers who don’t pay for the Sky Movies add-on can download TV shows from Sky channels and from partner channels like Nickelodeon, Disney and HBO — including HBO hits Girls and Game of Thrones, AMC’s Mad Men and Fox’s The Following.

Once users download Sky content, it’s not to keep: “Sky Movies content can be watched for up to 30 days and once viewing commences is available for 48 hours. Most other Sky content can be watched for up to 7 days and once viewing commences is available for 48 hours.”

Other U.K. companies are also experimenting with downloadable video. The BBC’s iPlayer lets users download BBC programs to computers, iPhones and iPads for offline viewing. (Content can be watched for up to 30 days, with playback available for seven days after viewing begins.) The Amazon-owned Lovefilm doesn’t allow offline viewing, but plans to do so.