Found dog, need advice

Tonight, a dog followed me home.

I saw him earlier when I went over to a friend's house--half a block away, he was following a couple of joggers, and I thought "gee--I wonder why they don't have their dog on a leash." It was because it wasn't their dog. When I came home later, the dog followed my car the half-block up to our driveway, and then up to the front door. He was extremely friendly--I'd be shocked if this animal wasn't someone's well-loved pet. As I write this, I think the dog is still on our front porch.

I took a picture of the dog, and posted ads on Craigslist, Backpage, and Petfinder. Other than that, I don't know that to do. I don't dare bring him in--I can't know he'd be safe or OK in the house. I'm hesitant to even feed him or give him bedding--if he lives near here, I don't want to deter him from going home on his own. However, he doesn't have any collar. Lost it? Indoor dog who never had one and got out anyway? Who knows? I also worry I'm turning away an abandoned dog.

If you know someone who lost a dog in Orange Park, FL, please have them look at the pictures. If you have advice for me, I'm listening.