San Francisco  - Social networking leader Facebook plans to boost its 1,000-strong staff by 50 per cent as it hopes to expand its user base from 250 million to 1 billion, company founder Mark Zuckerberg said in an interview published Monday.

Zuckerberg, 25, said the recession had helped Facebook hire top talent as other companies laid off workers. "No one else has been hiring. It's been a great environment for us because the economy has helped out."

He did not give a timeline for when the company hoped to reach 1 billion users, but said that he was determined to keep a lid on costs as the company continued growing, and aimed to reach positive cash flow next year. The young entrepreneur cited Facebook's bare cement new headquarters as a symbol of his frugality.

"The thing I want to remind people of is we're way closer to the beginning than the end," Zuckerberg said. "A lot of times buildings can be a signal that you've made it. I would rather that our building feel much more like a very large garage."

Started by Zuckerberg in his Harvard dorm room in 2004, the privately held company had received investments of some 600 million dollars and is valued at some 10 billion dollars.  (dpa)