I don't put the dog's name on there, but do put all our phone numbers. On a few tags I also put microchip numbers on them, along with their photo on the tag (dogtagart.com) We use a rubit clip to put on various collars. If we have workers inside the house I put a collar on the boys with our phone numbers embroidered on them. Normally our boys don't wear collars inside because of their extreme play and the risk involved.
Her name and my cell phone number.
She has a tag that says she is microchipped, and a tag that says she has had her rabies vaccine and has my vet's phone number.
She also has a tag that says she is registered with the city.
"Reward if found" and then all if our phone numbers. It really doesn't matter if they know the dog's name or even our names. I use the space to encourage people to call us ($$$$) and give every single number that may find us.