Of course it´ll be a source of energy in the future, but not the main one and its develop is not as near as some people want to believe. You see, with oil prices go up every day, and to deal with that reality, it´s necesary to find other ways to generate energy and wind power has been proven as a very good alternative. Also, consider that mankind has started to take conscience about the environmental problem and this kind of energy is absolutely clean, which means that it doesn´t generate any pollutant substances.
I see 2 problems regarding this tecnology: the first one, as Xcalibur said, would be the prices of raw material to build the whole system. However, Science is developing new materials day after day, so in that order, I believe that sooner than later it will be created materials which production cost will be chepear enough to knock down wind farm prices.
The second problerm I see is that you need an especific wind speed to use this tecnology. As far as I know, you need a speed wind average of 16 Km per hour to take advantage more appropriately of the wind power and that´s is a pity because not all the countries fullfill with this requirement. Nevertheless, I am very optimistic that Scientifics will find a solution to fix this problem and turn this tecnology in a more accessible one.