Add one zero.

Remember that Twitter works in multiple countries and in different languages. Then there is a lot of face to face meetings required, so add offices and service staff as well.

1-1,5K would sound reasonable for global sales and customer services.

I would agree, but I think their sales is doing a terrible job if they have that many and are not bringing the appropriate amount of money.

I would blame management/top more, than sales. Sales can work only with products they were given. AFAIK Twitter was pretty aggressively hiring 2-3 years ago sales reps across the globe and they were stealing top employees from FB and co.

I would assume that it is the lack of products/top commitment that causes poor sales.

I agree again, I think there is a lot of blame to go around in Twitter, also another reason why I think they could have a healthy purge and move forward with some fresh vigor.