LOS GATOS, Calif. -- Netflix's earnings quadrupled as its line-up of original programming helped the Internet video subscription service attract 1.3 million more U.S. subscribers during its latest quarter.

The third-quarter results announced Monday are the latest evidence of Netflix's increasing popularity. The Los Gatos, Calif. company ended September with 31 million U.S. subscribers, eclipsing the estimated 29 million subscribers that HBO's 41-year-old pay-TV channel is believed to have.

The quarter covered a three-month stretch ending in September that featured the debut of two series that could only be seen on Netflix.

Netflix earned $32 million, or 52 cents per share, in the quarter. That compared with income of $7.7 million, or 13 cents per share, at the same time last year.

Revenue rose 22 per cent from last year to $1.1 billion.