I was recently given an old HP Omnibook xe4100 laptop. It’s got a 1.1GHz Celeron CPU, 512MiB RAM and a 6GB hard disk. So it’s not blazingly fast, but it’s good enough for the journey to and from work on the train. I have an Ubuntu sticker on the lid of it which anyone facing me can see when I am using the machine.
Last friday I was sat on the train, headphnoes on whilst I typed on my laptop. I noted when another passenger got on the train that he glanced at the sticker a few times. It looked like he wanted to talk to me, but my headphones made that difficult for him. So I removed my headphones and packed away my MP3 player. Pretty much straight away he said “I appreciate the sticker”.