One of my favourite quotes is from Walter Benjamin: “A chronicler who recites events without distinguishing between major and minor ones acts in accordance with the following truth: nothing that has ever happened should be regarded as lost for history” (On the Concept of History, 1940). This is the method I try and follow with History is Made at Night - no detail is too small for recording.
Many others in the blogospere seem to be operating on a similar basis, documenting every available piece of evidence relating to their particular obsession, nowhere more so than in relation to music. As an example one of my recent discoveries is Excavated Shellac, dedicated to '78rpm recordings of folkloric and vernacular music from around the world'. Here you will find fantastic old recordings from all around the world not to mention images of some gorgeous slices of vinyl and their archaic labels.
Critiques of blogging sometimes give the impression that it is all about ill-informed comment and subjective rants. Granted there is plenty of that, but there is also lots of good qualilty research in progress and primary source material being put out there on blogs. My only concern is how fragile this is - held on private sector browsers, and at risk of being deleted if the blogger loses interest, or perhaps dies. Our collective cultural databank is being extended by the efforts of a million bloggers, but at the same time whole chunks of the social memory of the human species get wiped just because somebody can't afford to keep up their broadband payments.