If I had to pick a point of fragility for Google it is that the founders have set up the company such that they exercise dictatorial control. This can be good,

If I had to pick a point of fragility for Google it is that the founders have set up the company such that they exercise dictatorial control. This can be good, but it's a question mark what will happen once that control is passed to other hands. Further, Google makes most of its money from advertising and it's search engine. They're one competitor away from being in serious trouble. So far Google has beaten them all off but there are a lot of very smart people out there who want to cut into that very profitable business. In the plus column for longevity is a very large cash hoard. However, history proves that companies can vaporise their cash overnight in ill-advised acquisitions.