This note is about the difficulties of forecasting. The investment analysts are generally very optimistic about the future. When coupled with a focus on individual companies, they can end up forecasting that all companies will increase their market share. I will illustrate with the online advertising industry. The chart below highlights nine important companies in the industry. Google is the leader with more than 50% of the market. Facebook, Baidu and Twitter are the promising up-and-coming companies. Microsoft, AOL, and Yahoo are yesterday's companies.