Ten-year-old Tigger is big on social media. The internet is the only place the diminutive Chihuahua/Shih Tzu/Pomeranian mix might be considered big.

Before getting adopted this week, he spent about a year building a formidable social media following as a resident of the Old Friends Senior Dog Sanctuary in Mt. Juliet.

More than 1.8 million Facebook users around the globe have become fans of the nonprofit organization, which has cared for approximately 700 elderly and/or disabled dogs since its 2012 inception. Another 103,000 people follow Old Friends on Instagram, others have created their own fan pages for the dogs, and at any given time, dozens of people are watching the dogs eat, nap and play via webcam.

It’s easy to see why OFSDS has such a devoted following. Its Facebook and Instagram pages are a soothing, endless feed of the 105 dogs who live at the sanctuary. (Another 200 live in foster homes within a 100-mile radius of Nashville.)

And the comments sections, which are typically among the internet's most vicious hellscapes, are uniformly positive and civil. "This is the first thing I want to see after I get to heaven," proclaimed one Facebook user about a photo of a dozen dogs eagerly waiting for their walks.

"Queens wish they had her elegance," wrote another fan on an Instagram post featuring senior dog Chanel high-fiving her caretaker. "Goddess."

QUIZ:Which pooch at Old Friends Senior Dog Sanctuary are you?

"It's so easy to find negativity (on social media) that attempting to be the one positive thing out there really helps us out," said Kat Simpkins, the sanctuary's dog care manager. "Seeing how much these dogs mean to people is a little wild...that's one reason to keep going, because I know if it means that much to them, they're spreading the word to everyone they know."

Through the internet, people watch sick and scared sanctuary newcomers — some of whom have never had homes or proper veterinary care before — transform into playful, healthy members of the Old Friends pack. They share photos and stories of their own dogs and buy T-shirts depicting their favorite residents, including Mack, the blind party animal. Announcements about dogs' deaths are met with intense outpourings of grief.

Tours are offered three days a week and draw visitors from as far away as Eastern Europe, said sanctuary co-founder Michael Goodin one recent morning, raising his voice to be heard over a chorus of hungry dogs ready for breakfast.

"A young couple went on a tour and they were just so excited," he remembered. "I found out they were from Lithuania, and they said Tigger had this huge following there. That was pretty funny."

"I started the Facebook page in March of 2012, and I remember it took me three months to get to 50 followers," added Old Friends co-founder Zina Goodin. "I think by the end of the year we had about 1,000...Then we just kept posting and it kept getting bigger and bigger."

If the Goodins are bemused about the dogs' international celebrity, they're thrilled that it helps raise awareness about the need for homes for senior dogs, who have far lower adoption rates than younger dogs and puppies. In addition to running OFSDS, the couple also leads workshops for people interested in creating their own senior dog rescues.

Said Zina Goodin, "Senior dogs are mellow, they're sweet, they really do appreciate the home, and they truly need the help."

Take our quiz and find out which Old Friend you are. Click here if the quiz does not appear.

On Saturday, OFSDS is hosting "A Doggone Good Old Time" at Charlie Daniels Park (1075 Charlie Daniels Parkway in Mt. Juliet) from 10 a.m. - 4 p.m. There will be live music, food trucks, vendors, dog-centric activities and more. This event is free and open to the public.

For more information about Old Friends Senior Dog Sanctuary and ways to contribute, visit oldfriendsseniordogs.com or facebook.com/OldFriendsSeniorDogSanctuary.