About the 'real' entrepreneurs who don't know what Twitter is, I often see small companies who could save or make a lot of money if they had one full-time programmer or engineer. The cost is usually too high for them, or it is unlikely they would find someone passionate enough about their business to do everything that could be done without well defined directions.

An advantage every engineer or programmer has is that if he/she starts any business, he/she could also play that role. I think it is a huge advantage, and it is a big reason why I like to be a part of non-engineering endeavors.