Where is Blogging for Money ‘Passive’?

Perhaps the main area of where blogging has an element of ‘passivity’ to it in how it can earn an income is when it comes to your archives.
I’ve been blogging now for close to 4 years and in that time would have published over 20,000 posts across my own blogs. While the writing of these posts is anything but passive (more on that later) the great thing about it is that even after those posts drop off the front page of a blog they continue to have earning potential.
In fact as I look at the most popular pages of my blogs (and the ones that earn the most) - the vast majority of my income comes from my archives - posts I’ve not thought twice about for months, if not years.
In that regard - that income has a passive element to it - old posts are like an investment that continues to earn an income into the future.
Set and Forget Income Streams - One of the great advances from the last few years in generating an online income has come from the improvement of advertising networks like AdSense which allow publishers to add a snippet of code to their blogs that will automatically run ads on the blog over time.
While you can (and should) definitely work on your ad optimization - many bloggers get to a point with their ads that they are able to largely set and forget them. The ads will earn an income and the cheques (or direct deposits) will appear each month. There is no searching for or negotiation with advertisers - the system handles it all for you. This takes a load off many publishers minds and allows them to concentrate on other activities of running a good blog.
Put the idea of Archives and set and forget income streams together and there is an element of passivity to blogging for money. Add to it that money made from blogging doesn’t depend upon you being ‘open for business’ to make money (ie I make more money during the hours that I’m asleep than when I’m awake due to my time zone) and I can understand why people might describe it as a passive income