It's true, but quite reductive, that that these smart people are working on these interesting projects in the service of advertising. If you think in these term

It's true, but quite reductive, that that these smart people are working on these interesting projects in the service of advertising. If you think in these terms, Walter Cronkite worked for ads, too. Also, consider that to the extent that these projects are open-sourced or otherwise widely available, they create external value. Go will not be solely used by Google, though it may have been created to serve Google's aims. Likewise for whatever messaging system Twitter built this week.