Having (and handing out) business cards can be a good strategy at conferences, not just when job hunting. Of course, when we're handing them out for strategic networking reasons, lots of other grad students are also handing out their business cards for the same reasons we are! Since these other graduate students are part of our peer networks, and since the professors we may want to connect with likely also have cards, we may well be going home with a pile of business cards. So, what can we do to make our (hopefully manageable) haul more useful?
One option, of course, is to make a smaller number of meaningful connections, rather than taking the card of everyone you possibly can. I like this method, because there's not much point to taking a card from someone I'm unlikely to actually follow up with. Too many cards can easily become academic clutter, even if I'd genuinely like to chat with everyone whose card I took. (To everyone I took a card from and never followed up: sorry! Yes, this is what went wrong.)
I also try to send my follow-up emails while I'm still at the conference, as an evening activity. I might use the send-later function so my email arrives in my new contact's in-box after they're home and checking email more regularly. If possible, though, I write my end of the follow-up the same day we had the conversation. This keeps the whole conversation fresher in my mind than waiting.
Another option, which I use in combination with being selective about whose cards I take, is to write notes on the physical business cards. The card already has a name and contact information. I add some notes about the conversation that led to my asking for the card, or them offering it. These include answers to questions such as: What did we talk about? What do I want to follow up about? Which research interests do we have in common? Were there any shared identities we wanted to talk about? Was there a project we were considering collaboration on? By making sure I have the notes to remember why I wanted to get in touch with someone (which may only require answers to a couple of the questions above), I'm far more likely to actually do it, even if it takes a while. (I'm not going to remember what I wanted to follow up about several weeks later without notes. I might remember with notes.)
By using these methods together, they can support each other. When I can write emails in the evenings at the conference, my business card notes are still useful, because they help me remember which person goes with which email. And once I’ve sent the email, I can either note on their card that I wrote the email or get rid of the card. Following up with as many people as possible while I'm still at the conference gives me a shorter to-do list and fewer cards where I need to work from notes when I get home. Selectivity similarly helps keep the list shorter. And by following up each day, I make space in my head for the next day's meaningful connections. Between these methods, I eventually follow up on most connections I make at conferences.
What do you do with the business cards you collect?