At our next company hackathon, I'd like to make a twitter bot for Plaxo where you can follow it and get DMs with all your Plaxo notifications (e.g. "John commented on your status update", etc.). The biggest challenge I'm facing is how to know when a notification gets generated that the recipient is currently a follower of the plaxo bot on twitter. I need the lookup-function to be cheap when notifications are being inserted (since that happens a lot and in most cases the user will not be a follower), so that means probably setting some bit on the subset of our users that have hooked up their twitter account and are following our plaxo account. So that means we'll need some offline mechanism for periodically looking for newly-added and newly- removed followers on twitter and setting the bit on the right plaxo accounts. But is there an efficient way to do this?
I understand that when someone starts following your account, you can get an email and use that as a push-notification to tag the appropriate user. But you can't get any notification when someone stops following you, right? Does that mean we'd have to fetch our entire follower list every time and do a full diff with every user in our system to update things? Seems really expensive. Any better suggestions? I'd imagine this is a pattern that will become more common as existing services with existing userbases want a way to interact with their users via twitter. Thanks in advance for any help anyone can offer here! :) js
