One company that got a lot of attention at the ESRI User Conference was Adapx, who launched their application which allows you to use a paper map as an intelligent digital input device. John Calkins of ESRI demonstrated this in the plenary session with various other "cool things". Several others have blogged about this, including Joe Francica at All Points Blog, who includes a short video of a demo of the system. The underlying technology comes from a company called Anoto, who have been around for a while - I talked about this technology in a presentation at the GITA conference in 2004. The trick is that the paper is "watermarked" with a pattern of dots which allow the pen to determine its location in a very large coordinate space. One of the clever things about the solution is that the pen and paper is used not just for entering the location of geospatial features, but for other "user interface" actions such as specifying the type of feature to be captured. So you can click on a legend at the bottom of the map to say that you are about to add manholes (or whatever), and subsequent clicks will be treated accordingly. You can also capture attribute data using printed lists, or handwriting recognition. All of the intelligence to interpret these actions is applied when you upload the data, so the pen needs to store the sequence of events. This also means that if the system doesn't register a click on the legend, or registers the wrong item, you could get a significant amount of data captured incorrectly without the user realizing, as they have no real time feedback on what the system currently thinks they are doing. I guess time will tell whether this is a significant issue in practice or not. But certainly many field users will like the concept of being able to use paper and pen for input.
So it will be interesting to see whether this really takes off for widespread use. I think that one of the most promising uses is probably in areas where people currently use large paper maps or drawings in the field, such as on construction sites. It has always been a problem to provide the same capabilities on a laptop or tablet screen that you can get from a large paper construction drawing with a group of people standing round looking at it - you just don't have the real estate on a screen to show all that detail at one time, and share it with a group. The ability to mark up a map digitally in this situation could be very useful. Still for many work scenarios, for example where people visit lots of different locations which are not predefined, a digital display is likely to be more useful than having to carry very large numbers of paper maps.
But it's definitely an interesting alternative input mechanism in a number of scenarios, I look forward to seeing how it does in the market!