June 15, 2010 — I think it's interesting to ponder the value of information over it's lifetime.
Different types of data become outdated at different rates. A street map is probably mostly relevant 10 years later, while a 10 year old weather forecast is much less valuable.
Phone numbers probably last about 5 years nowadays. Email addresses could end up lasting decades. News is often largely irrelevant after a day. For a coupon site I worked on, the average life of a coupon seemed to be about 2 weeks.
If your data has a long half life, then you have time to build it up. Wikipedia articles are still valuable years later.
What information holds value the longest? What are the "twinkies" of the data world?
Books, it seems. We don't regularly read old weather forecasts, census rolls, or newspapers, but we definitely still read great books, from Aristotle to Shakespeare to Mill.
Facts and numbers have a high churn rate, but stories and knowledge last a lot longer.