Social networking for the furry set

Since she and her husband separated, Frank can't be with her dog, Scout, every day, but she can share news about her and get updates on Dogbook, a third-party application of Facebook.

"It left a big hole in my life when she went to live with my husband ... then we got connected on Dogbook," said Frank, 58, of Silver Spring, Md., who also maintains a profile of her cat, Cinnamon, at Catbook. "The fun part is that I can send little messages to Scout," which are read by friends.

Frank says she can give the pup virtual hugs and scratches behind the ear. She's also been able to hook up with old friends and their pets through the applications, including a woman she went to high school with and her cat. "It makes me feel like I'm more connected," Frank said.

At Dogbook, canine owners can create Facebook profiles for their animals, find dog parks and products, and tag their dogs in photos. Major advertisers on the app include Purina, Toyota and Coke.

Geoffrey B. Roche, co-founder of Poolhouse Enterprises, which produces Dogbook and other pet pages, said the idea came to him a few years ago at the dinner table, and took off quickly. Now, there are about 2 million users on Dogbook and about 1 million on Catbook, he said.

The sites work, he thinks, because people see their pets as more than just animals.

"The dog goes way beyond what was just a dog. It becomes a family member," he said.

"This is a great way to keep track of pets' lives." Users "are as excited to show you pictures of their dog as much as their kid, if not more," he said.

Dogbook's recently launched iPhone application passed 80,000 downloads after just two weeks.