Pending on your goals, a blog format may really work for a non-profit web site or your own personal home page. Yet the medium of blogs with dated content, can create pressure to keep things fresh. Many bloggers buckle under the pressure of posting daily updates, but this may no longer be necessary.
Eric Kintz says that daily blog posts can sometimes be a liability.
ProBlogger Darren Rowse adds some qualifiers.
The bottom line for me is that each blogger must determine the goal and audience of his/her blog. For example, a more specialized blog such as cooking, history, or theology may only require weekly posts. Tech, politics, and news may be a different story.