> Facebook really wanted to stay in Palo Alto. Zoning restrictions made it difficult. They had split offices and eventually had to move. Twitter for some reason is sticking to SoMA but as the seedier areas gentrify and go up in cost, this is going to become increasingly difficult. At some point it's simply going to make more sense to relocate out of these kinds of areas.

In most firms, the people who are in a position to make a decision about relocating are the few who are able to compete successfully for expensive real estate at the current location.