I was sitting at home this evening when I heard a creaking sound coming from the ceiling fan, noticed a slight vibration, and though, "oh, an earthquake". If you've lived in Southern California a while you tend to note these quakes which are either very small or very far away or both, and then move on without much thought.
The USGS has a WONDERFUL site, earthquake.usgs.gov, that gives you all the data you could want about every earthquake, so later on I took a look. A 4.5 magnitude out near San Bernardino - enough to make you a bit nervous if you were close by but not likely to do any real damage. I'm about 80 or 90 miles away. On the site, there's a link - "Did You Feel It?" - you click on it and it collects your location and then asks you about your perception of the quake.
So how many geeky people (like me) do you think would go to this site for a small earthquake, click on "Did You Feel It?" and then complete the survey? So far, over 3,400 from all over Southern California. What a fabulous way to collect data about the perceived intensity of an earthquake, the range of perceptions, and the patterns of intensity in the area around the quake. I imagine someone at USGS proposing the idea and being told, "why bother, nobody would do that!" For a moderately large quake they get many tens of thousands of responses. (Of course, when the big one comes, the Internet's going down!)