Now, it's not uncommon to see that they're used to report, respond and build community around major world events and disasters, as traditional online news sources struggle to cope and blogs provide a more accessible, and often personal and first-hand view.
Of course, there are very many important reasons to remember the 9/11 terrorist atrocities in the US, but from a technological and communications point of view, they perhaps shot blogs from their geeky enclaves to centre stage, as people looked for places to connect with one another online and try to make sense of what was going on.
Wired News has an interesting article on how blogging grew out of 9th September 2001.
Another characteristic of many blogs is that they form a personal preserve of events: for example Dave Winer's blog entry for 9th September 2001 still stands, presumably unaltered, as do many others.
There's NYC Bloggers links page saved for posterity.
Blogging continued to report first-hand events during the Asian Tsunami, and the 7/7 attacks in London, amongst others, and developed from text and still images to include mobile blogging (moblogging).
Technology may sometimes be blamed for breaking community and depersonalising human relationships, but it can unite people across the globe in times like these. Long live blogging!