This lunchtime, whilst walking the dogs in the next road, I saw, you guessed it, a couple of 'Black Rabbit Lost' notices with a photo of said black rabbit.
I therefore phoned up the number on the 'Black Rabbit Lost' sign from my mobile and got an answerphone, so I left a message saying 'I'm sure you know this but...'.
Then on the way back into our road I phoned up the 'Black Rabbit Found' number and got a real live person who hadn't heard about the 'Black Rabbit Lost' sign in the next road and hadn't heard from anyone, so I said I would phone him back when I got home with the number I had rung (since I didn't know how to bring up the recent call lists on my phone), which I did.
Since I didn't leave either of them my name / number I don't know the conclusion, but I assume there was a happy reunion, so there is my good deed for the day. I am quite good at being public spirited as long as face-to-face human contact is not involved due to my S&M tendencies (shy and misanthropic), and even have the 'streetlights out of use' hotline programmed into my phone.