When The Beast went missing a couple of years back I just put my cell phone number on the poster. (He reappeared by himself, thankfully)
I didn't put and address, mainly because It was a bit upsetting to have to make the poster and the thought didn't enter my head at the time, as most people are tied to there phones it's the quickest way to contact someone.
From the point of view of a finder of a lost cat. When we had a random cat turn up in the house, which we game some food, it kept reappearing, and on an evening walk we found a poster describing said cat, a telephone number and address, which was about 1/4 mile from our house.
Back from walk cat was at the back door on the scrounge, we guessed for grub.
So we hoofed the cat into the Beasts' carry box and drove round.
People outside, gardening. I get out of the car and say "I think we have your cat"
The lady of the house was quicker of the blocks than Usain Bolt.
Floods of tears and screams from the lady who initially just grabbed the box without a word and rushed inside. Man of the house explained that the cat was quite old and had been with the lady since before the couple were married.
Chat about how cat had come into the house, kept coming back, hissed at the Beast.What we fed it and when.
After what seemed an age lady comes back with carry box, all red eyed, and still a bit sniffly. Repeat story to lady.
They ask where we live, tell them, handshakes and kisses all round and we go home.
Next day come home from work and there is a bottle of wine and a card on the doorstep.
From a, maybe slightly conceited point of view, having the address, and being able to, for want of a better word, surprise the family was a great feeling.
It caught a wonderful life moment; spontaneous emotion from the lady owner; no time to 'gather herself' before being reunited with her pet, and to see how much it means to her.
A rambling post, sorry about that