Google announced the release of its new indexing system Caffeine yesterday, and you may be wondering what, if anything, this may mean to you. The short of the answer is: not much.
As a searcher, Caffeine will supposedly work behind the scenes to bring you faster and more relevant results, in a more comprehensive way. Google visualizes it thusly:
Which essentially means that when you go to Home Depot to look at paint cards, you will be, instead, minisculized to the size of an atom and sucked into a vortex full of home electronics and user manuals.
In seriousness, though, the illustration is meant to suggest that the new indexing system is a much more dynamic and holistic approach to web indexing than their former, more hierarchical one. It should provide faster listing of new pages in the index, and changes to existing pages should show up faster as well.
Web content owners don't have to worry about making any changes to pages they have created, and searchers don't need to modify their search approaches. It does mean that pages in the Google Cache will see more frequent turnover, as blog resourceshelf points out, so searchers who would like to archive a current version of a page should begin to consider alternative ways to take "snapshots" of a page, since the more frequent updating will mean that Google Cache is no longer a viable option, as the index will most likely always be reflecting the current state of the page.