There's been a surge of interest in digital collectible card games and considering how hot free-to-play is now (at least among easily excitable marketing types), why would you not copy the hugely successful business model Magic: The Gathering pioneered, minus the cost of printing physical product?
Such is the direction Games Workshop has taken with Warhammer 40K: Space Wolf, an upcoming CCG based on the company's popular franchise.
The Warhammer license hasn't had a good run lately, with the most recent addition, Space Hulk, failing to impress critics and users alike. Rather than focus on producing one awesome game every few years, GW seems to prefer the "throw at wall, see what sticks" approach.
Unfortunately, the trailer for Space Wolf, in development at a studio by the name of Herocraft, doesn't provide one with a wealth of details... or optimism. Cards, one at a time, fly at the screen, showing unexplained mechanics, followed by an in-game example of said card's effects. Most of these effects involve one character damaging another, though there's a fancy one that has jetpacks.
Deck-building and earning cards via "missions and challenges" are mentioned on the official website, but these are facts one could probably have guessed.
As RPS' Graham Smith points out, the developer's previous games don't exactly fill you with confidence, but we should reserve judgement until we have more information. That said, the signs so far are not overwhelmingly positive.