When video game maker Jim Greer approached Silicon Valley investors to give him nearly $1 million for his start-up. he had an irresistible pitch: “It’s video games meets YouTube.”

He named the site Kongregate.com and last June began inviting game developers and players to test it. After Christmas he opened the site to users of all stripes, who can submit and play games free of charge.

So far, the advertising-supported site at www.kongregate.com offers 300 games that are rated by players, who chat online as they play.

“Not all of them are gems, but the top 100 are,” said Greer, 36, who founded the company with his younger sister Emily, 32, and offers game makers a share of the site’s advertising revenue.

Reid Hoffman, founder of business networking site LinkedIn and a former PayPal executive, said timing played a big role in his decision to become an investor in the company.