Admittedly, a business card is just as easy to lose as a scrap of paper. (I spent the last fifteen minutes looking for one that I knew I'd been given last weekend before finally finding it.) I learned early on how easy it is to forget why I accepted someone's business card. Was it because it was just offered to me and I accepted it? Was there an information-gathering purpose attached to the exchange? I try to write down why I have a business card on the back of the card as soon as I've received it for fear of forgetting. For I will forget if I don't - I have a number of cards here for which I have no memory of the person or circumstances attached to receiving it.
I give away business cards as often as I can, for I will never be able to go through all 250 of them before I finish this degree. If I do manage to, it'll be because I've found some new and more efficient method of handing them out productively, or because my degree ends up being a few years longer than I'm currently expecting it to be. At the end of my current degree, most of the information on the card willl cease to be valid, you see. My name won't have changed, but just about everything else will. At this point it's a challenge: how many cards can I legitimately give away over the course of the next few conferences, while still giving each card under normal and appropriate circumstances? It's a whole different reason to network.