1. There is not enough information in the original tweet to determine if this person is working full-time at either company or part-time. Both companies employ

1. There is not enough information in the original tweet to determine if this person is working full-time at either company or part-time. Both companies employ enough contractors. 2. As other comments said, this might not be ethical but may still be legal. Full-time employees are not hourly, and as long as they do their job hours shouldn't matter. 3. If in California, there is no non-compete. 4. Due to it being FB and Google, they can get into trouble from an IP standpoint of they leak or use IP from one at the other. 5. Logistics can be interesting. But it is certainly possible for a person to claim they are remote from different timezones at each company to minimize conflicts. 6. Still I can't see how they can continue this for long if friend of friend already knows about this. Someone in there social circle will get jealous and report them.