Space and time are enigmatic theories of the greater universe but also useful media concepts.  Space can define a newspaper ad in column inches or the location of a banner ad on a web page.  Time can be the length of a TV commercial or an exact time of day it is scheduled to be broadcast. 

For this discussion we examine not space and time, but space and distance.  Most media content (with some obvious exceptions) can be consumed in a public or private space.  Just choose your delivery device.  It’s not easy to carry around a TV set but you can find them in many public spaces like bars, airports and waiting rooms.  Likewise, computers and especially laptops are used in public and private spaces like offices, conferences rooms and coffee shops.  The mobile phone needs no discussion because we have all seen them used everywhere and in many inappropriate public spaces.  The space where these devices are used is much different from the distance in how the media is best consumed.  Although screen sizes for all devices can vary widely, the approximate optimal viewing distance is:

Television -- 10 feet

Internet -- 2 feet

Cell Phone -- 1 foot

The video ad that you produce for TV does not necessarily transfer to the mobile device – not only because of the optimal viewing distance factor, but because you use the oven to bake bread and the microwave to make popcorn.  The creative message should be designed with the media delivery system in mind.