We had the same challenge going on a couple of months back. There wasn't too much interest in it then either. I mean, a lot of people started with it but then didn't follow up or continue. At the time, I was in a walking contest at work and was walking in excess of 25,000 steps a day. That may have scared some people off, I don't know. But, I did make it clear I was in a contest and was deliberately walking as much as I could to win. A few other people were involved but not too many.
That being said, you should wear the pedometer the entire day, from the moment you get up until the moment you go to bed. 10,000 a day is the minimum that every one should be walking. That is not the amount for weight loss, it is the amount for good heart function. Anything over that is for weight loss. It may be hard to get up to 10,000 a day for sedentary people, but you need to get up to that amount as soon as possible to reap the benefits. But, as long as you wear the pedometer every waking minute, 10,000 isn't as hard as it sounds. Don't get discouraged, just get moving!!
If I can find a decent pedometer, I'll join up again too. I always enjoy a good challenge. Just need to get to store and find one. All my old ones broke.