One of the newer methods of generating a somewhat passive income, is the vehical of the blog.
Search engines love the blog, because it updates often, and generally is structured towards answering a question (the most common form of search)
As a result, they've become pseudo mini-googles. (I just came up with that. I like the sound of it, though... pseudo mini-google.)
That being said, there are a number of ways to monetize one's blog.
There's the things you see to your right -->
Those are google addsense. They put adds there, and, the more people that come to the blog and see them, or, better yet, click on them, the more money the blogger makes.
The next way is through product reviews and affiliates.
For example, I happen to greatly enjoy the Meditation on Twin Hearts - its a guided meditation which was taught to me by one of my spiritual mentors. So, if I were to recommend that to you, and you were to purchase it after clicking on that link, I'd get about $4.
Now, that's a little off-topic of an example, so, instead, let's go with one targetted specifically to those wanting to manifest wealth in their lives; such as the MMI hypnotherapy CDs, of which I own the entire set for my Shinka Martial Arts Library (the dojo that I own). They're a little pricey, but our students have access to them for free.
Side note: That link I just made there has an art to it as well. See, every time I write "Shinka Martial Arts" and link to it, web spiders look for things like "shinka" and "martial arts" in things, and if they point to other things that are related, the SEO on shinka.ca goes up.
It doesn't make passive income directly, but, it increases the likelyhood that people'll find my dojo over another's in their web searching.
Now, the amazon.com referals you saw above were for specific products, and were blog-integrated (meaning blogger.com sets it up for you and makes a neat plug-in and everything)
What you can also do, is use an affiliate network, and profit from virtually any product on the net (so you aren't limited to amazon)
For example, paydotcom.com is a middle-man for affiliates and people needing affiliate-ing.
You can also promote your products there as well, and thusly have access to their vast database of affiliates, who are looking for items. I promoted a product of mine on there as well, mostly to increase my SEO (as people will create links to it, which makes shinka.ca more important as above) but the cash from the sales is nice, too.
Now, you can also get affiliate income via recommending affiliates. Yes, that's right. Because I just told you about PDC, if you sign up and become a successful affiliate, PDC gives me some $, too.
Affiliate income is one of my favorites, because its so win-win. As long as you're ethical, and only recommend things you actually like, you're increasing the awesome in this world, and, at the same time, getting paid for it. Win/win/win (the third win is for whoever's product you're endorsing)
Once your blog is sufficiently popular, you may also get specific, targetted requests to put in specific, targetted products.
This is basically when Tom Cruise drinks Coke on screen instead of a nameless soft drink. Money exchanged hands, there.
Now, personally, I wouldn't push coke, because its bad4u, but, I think you get the idea.
How could you best encourage a blogger to blog?