I believe 4K displays will start to pick up in 2014 in a very fast paced introduction.
Most movies are still not being shot in 4K resolutions yet though - which makes content scarce at introduction. Movies are typically being shot at 2K resolutions, and up-sampled to 4K - reason for doing this is that the computing resources required to do special effects progressively get more intense as the number of pixels increase in a production.
Lenovo has some announcement in CES this year, citing 4K monitors for PC - one such monitor is the Lenovo ThinkVision Pro2840m (28-inch, 3840 x 2160). It will be interesting to see the adoption rate of such "high-end" monitors. Games may not be able to drive such monitors yet as 3D graphics card may need to double their performance before we see 4K games. Retailing in April 2014 for approximately USD$800. Let the 4K war begin!