If that isn't enough for people we are open to including privacy controls, like only allowing people you follow to view your location, but we wanted to see what people wanted from the site before we went down that road.
I've been thinking about this particular problem for quite a while because of an idea we had about two years ago called 'lifeyarn', the plan was to couple mobile pictures with date, time and locationstamps into a threaded representation of your life. You can then use the threads to meet people and do all kinds of interesting things with them (who was where on what day, who attended that dinner and so on).
The possibilities for abuse are endless, you really have to be careful with that and pro-active, don't wait until a bad thing happens and then plug the hole.
I'm definitely interested in how best to solve the privacy problem. I'm not really interested in the majority of location services because they tend to track you all the time, my thought was that making it more of a on demand thing would help to alleviate the fears but it may not be enough.