(Reuters) - A Web site set up to help find missing four-year-old Madeleine McCann has received more than 50 million hits, its operator said on Friday.

More than 7,500 people have left messages of support on the www.findmadeleine.com site and 55 million hits have been counted since its launch.

Thousands have downloaded appeal posters and forwarded an email chain letter started by Madeleine's family. The little girl disappeared from her bedroom at a hotel resort in Portugal on May 3 as her parents dined nearby.

"It is booming," said Calum MacRae, director of Infohost, the Scottish IT company behind the findmadeleine site. "We didn't expect this number of people.

"We had 10 million hits between 10 a.m. to 4 p.m. on Thursday -- our server just gave up, but we resolved that within five minutes."

The website www.bringmadeleinehome.com was launched on May 9 and it changed to www.findmadeleine.com on Wednesday.

Messages of support from across Europe, the United States and Australia have been posted on the site.

"You are in my thoughts every day," wrote Heidi from Finland. "I pray that she will be found soon safe and well."

Debbie Bates, from Australia, wrote: "As a mother of two, I cannot imagine for a moment what you are going through."

Parents Kate and Gerry McCann are taking "immense strength" from the messages, said family member Michael Wright.

"Their purpose is to turn hope into action," he said on Thursday. "We want everyone to have an image of Madeleine in whatever country in Europe they visit."

A video appeal will be shown on Saturday at the FA Cup final between Manchester United and Chelsea at Wembley Stadium.

Portuguese police say they have insufficient evidence to arrest anyone in the hunt for the girl.