There are many worthy causes that deserve to be promoted to the world. If you're a blogger like me, your first impulse when discovering a worthy web site might be to blog about it. If you think it's worth being promoted over a longer period than what can be expected from a single blog post, your next impulse might be to add a reference to the web site in the margins of your blog, typically in the sidebars, header, or footer.
Unfortunately, there are too many worthy causes in the world. It's unfortunate in that this is because there are too many problems in the world. But it's also unfortunate since the margins of your blog will soon become too cluttered and your readers will start glossing over all the causes you think are worthy. Or at least that's what happens to me when I see a sidebar that has too many things in it; interesting content tends to get drowned among everything else. That's why I've kept the margins in Stochastic Scribbles pretty minimal.
However, I've always felt the temptation to put in links to sites that I feel a lot of people should look into. One way to succumb to the temptation would have been to show only one or two links and manually rotate them with others every so often. This is too much work for lazy old me, though. But I found another way to succumb to the temptation without cluttering the margins too much using Google Ad Manager, which I had been using elsewhere for a while now.
Google Ad Manager is an online system for managing all of your online advertisements in one place, regardless of whether they were created by you or your client directly, are from AdSense, or are from any other advertising network such as the Yahoo! Publisher Network. By providing advertisements for worthy causes as house line items, all I have to do is set them up and let Google Ad Manager do all the work of rotating the links.
Content rotation using WordPress plugins would be another approach, but it won't work so well in tandem with caching. And I'm not entirely without greed: I also want the option of showing high-paying advertisements from Google AdSense or the rare direct client every once in a while. Since I'm providing free house advertisements for worthy causes, I also need to set for them a non-zero value CPM, which basically tells Google Ad Manager to treat free house advertisements like they earn money so that they're not overridden by every paid advertisement.
I'm not quite sure what a good value CPM would be, though. If I set it too high, then paid advertisements would never show, not to mention that it would probably put an overly expensive lower limit on hypothetical direct ad sales. If I set it too low, then the house advertisements won't show often enough. For now, I've set the value CPM for each house line item to $1.00, which seems to be working fine enough. To spin this nicely, this would be equivalent to donating a dollar's worth of advertisement space for every thousand visits.
Another nice thing about Google Ad Manager is that it can target advertisements to an appropriate audience. For example, I have set it up so that it doesn't show No On Prop 8 outside of California, obviously because the site is about a ballot measure applicable only to the state in question. Another example is to show the US web site for the International Year of Astronomy only to readers in America.
Hopefully, the house advertisements and the occasional paid advertisements won't annoy any readers out there. With only one item shown at a time, they should also be much more noticeable than if I had crammed them all into the sidebar. And I have a confession to make: While I've always wanted minimal clutter, I thought the sidebar here was a bit too bare. The new advertisement space strikes a nice balance pleasing to me.