Friday, July 10, 2009

Signal to Noise

This posting is sparked by a conversation between Nigel Green and me. We were having a spirited discussion about choices in following people in Twitter. But the concept generally applies in almost all event based architectures.

The fundamental principle is that it has to be somehow worth it to sort through the whole mess of communication to get what you need or want. Thinking in interface architecture terms, a point to point interface has a very high signal with very little noise. However, tailoring the communication channel is very expensive - at least for the originator of a message. Similarly a total mind dump of everything you are thinking about at a particular moment can have a very poor signal to noise ratio when viewed from the perspective of someone trying to decode the message.

I have used the example of the Christmas Letter before - the letter that contains all the family news and is sent to every acquaintance. For the originator of the message, it is a very efficient way of communicating stuff. No thinking about what each individual subscriber cares about - let the subscribers figure it out. If there is enough signal in the letter, then filtering through the noise is worth it. If not, it goes quickly to the recycling bin.

Likewise in social media. As a twitterer and as a blogger I don't know what individual followers are going to want. As a blogger, I don't even know who the followers are. And I don't want to. If people find that the signal is rich enough they will follow, if they don't they won't. A very efficient way of information delivery - and a very handy simplification technique in event driven thinking. The basic question is, "Is the signal to noise ratio high enough so that it is worth me continuing to listen on this channel, or are there are other channels with better ratios?" As a subscriber I can often make that choice.

Twitter is such a great example, because the space is flat. When I tweet, it could be on any topic that I find interesting and relevant. To me, the twitterer, it is all signal. To you the follower it is probably mostly noise. If there are occasional useful signals you will continue to follow, if not you won't. Attempting to put some kind of ontology over twitter defeats the purpose because the publisher has no clue which permutations of tags are relevant to any given listener. I regualraly unfollow twitterers when the signal to noise ratio degrades too much.