A common theme of mine is simple, elegant solutions and this meets that criteria bang on. Posterous is a lite weight blogging application that is as simple as a 'tweet' and as comprehensive as a blog (without all of the bells and whistles).
How simple is it? You basically start and manage you blog via (any) email account. There is no set up, and your blogs are posted by sending an email. Worried about attaching video, audio, pictures, etc? Don't, you send / post them as an email attachment. It even unzips and posts files, automatically.
If you are thinking about starting a blog, I would start here for sure.
If you are thinking about starting a business, I would start here for inspiration as well. This business was started for less than $20,000. There are a few other company presentations wrapped up in this video but here is a link to the Launchpad session hosted by Guy Kawasaki that featured Posterous and another company I love called Goodguide.