It struck me in adding an entry to my Wi-Fi blog in which I credited a reader who sent a URL in to a useful article that merely by sending that to me and having me link to him in turn in thanks, that I've boosted his Google rank. All of my blogs are highly ranked -- thank you, everyone, for linking to me -- and thus my magic URL wand goes plink, plink, plink.
I saw a related phenomenon this last month. Also on my Wi-Fi blog, I have an article called Cheap Home Gateways that describes several sub-$300 wireless Wi-Fi access points that support various cable/DSL modem gateway features (DHCP, NAT, firewall, PPPoE, etc.). I couldn't figure out how to make the kind of chart I wanted to at weblogger.com, so I created essentially a big blank canvas on which I could offer up a huge color chart for someone to review or print out. I put that at my site here a couple of months ago.
What I didn't anticipate is that because glennf.com is more highly ranked than the Wi-Fi blog, that people searching for cheap wireless get my glennf.com fairly highly ranked, while the Wi-Fi blog is much lower. This ranking difference has put money in my pocket, because each item that's in the cheap list and is available at Amazon.com has an associate/affiliate link. Revenue from these link last quarter: about $150 per month. Revenue this quarter? $500 per month (so far).
Who says blogging doesn't pay?