Facebook's chief technology officer Adam D'Angelo, a school friend of chief executive Mark Zuckerberg, is leaving the company.
The 23-year-old helped Facebook cope with its rapid expansion - the company has just borrowed another $100m to buy new servers. The money comes from TriplePoint Capital and will all go on servers.
The company already needs 10, 000 servers to keep its service running and the TriplePoint money will be enough for another 50, 000, BusinessWeek reports.
D'Angelo has a bachelor's degree from California Institute of Technology. He was one of the first people Zuckerberg hired to help set the company up.
D'Angelo was feeling the pressure and, according to All Things Digital, believed his job no longer fitted with his interests and skills. He mailed Facebook staff on Friday saying he needed a break but would remain a strong supporter of the site.
He will not be replaced - instead, Facebook is looking to hire a vice president of engineering.
In other news, Facebook is making it easier to link to profiles from external websites. Facebook Connect will launch in the next few weeks and will let users connect to their Facebook profiles from other sites. It is not clear how issues of privacy will be dealt with, but on its developer blog the company said: "It's about giving users the ability to take their identity and friends with them around the Web, while being able to trust that their information is always up to date and always protected by their privacy settings."
Rival site MySpace has announced similar plans to open up profiles to external sites. ®