"A friend recommended it to me, and I think it's a lot of fun," said Yu, showing off avatars that include a girl with bunny ears and a man with a fishing rod.

"My father creates around seven avatars a week, one for each day."

Guo's challenge now is to make sure his company avoids becoming a one-hit wonder, like so many app developers before it, said Yan. Though MYOTee doesn't generate any revenue, Guo has a bit of a cushion because of the venture capital backing.

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"They have enough time to decide where they want to go," Yan said.

Guo and his Shenzhen-based team have tapped into a formula that has proved popular in China: borrowing an idea from overseas and customizing it for local tastes. Sina Corp's Weibo service is similar to Twitter, while 58.com Inc is a Craigslist-like site for China.

MYOTee is similar to Bitstrips, a Toronto-based company founded in 2007, which focuses on full-length avatars with backgrounds and scenery.

MYOTee concentrates on close-ups, emphasizing combinations of facial features and accessories.

Guo said it was a love of Japanese comics that lured him away from Tencent, a Shen-zhen-based company that develops software for mobile messaging, advertising and games. He admits he is not much of a designer, so he depends on his startup's four artists, including Lee.

"I love Japanese manga, especially One Piece," he said, referring to the popular series centered around pirates.

Guo said their goal of 10 million downloads for the whole year was ambitious because they wanted to motivate their team. They hit the 36 million mark by the end of June, he said.

After securing funding from IDG Capital Partners earlier this year, the team's goals are growing, with talks underway for a second round of financing, Guo said. He declined to say how much they plan to raise or with whom they are talking.

The funds will be used to double the team to about 20, helping them develop new products such as mobile games and social comics in the coming year, he said. IDG Capital did not reply to two e-mails sent to its Beijing team.