TheOptimizationIdiot - 11:23 pm on Mar 16, 2013 (gmt 0)
How can a web page be "stale" if it provides the best information on it's topic?
That's a complicated question to answer. I think the best places to start are with the patent applications and also understanding stale is not necessarily bad in all cases, but the question about why it may need to be changed or how it could be "more stale" than other documents has to do with way more to do with "what's on the page and how long it's been unchanged", cause freshness "cascades" like PageRank (for lack of a better way of explaining).
Anyway, if you really want to know the answer to your question the Hot Topics section [webmasterworld.com...] specifically the Historical Data Patent [patft.uspto.gov...] and also the associate thread here [webmasterworld.com...] are probably good places to start.