But, you need lots of readers willing to click on your ads

Keeping an online journal, or blog, can be rewarding. You can use it to share opinions or to keep in touch with friends. But you can use it to make money, too.

Some bloggers report making a few thousand dollars each month from ads. Unless you have droves of readers, though, your efforts will be less rewarding. But you might cover some of the small monthly expenses associated with hosting a blog.

Google's AdSense has become practically ubiquitous on the Internet. The AdSense program places small boxes containing text ads on Web pages. Companies large and small use the program.

Setup is simple. Once Google approves your application, you place some HTML code on your Web pages to activate the ads. Google's algorithm targets ads to your readers based on the page's content.

It works best with pages that are specialized. If your content is too general, Google can't effectively place ads on your page.

AdSense uses a combination of cost-per-click and cost-per-thousand ads. Per-click ads pay you a specified amount each time someone clicks an ad. Per-thousand ads pay you for each thousand ad impressions. An ad impression is one view by a unique visitor over a set period of time.

Google decides which you will get, based on what it thinks will be most successful. Google doesn't disclose how much it pays its customers, and it prohibits members from discussing how much they get.

The look of Google's ads can be customized. You can change colors and control their placement. Additionally, filters give you some control over what ads appear. You can block ads from specific Web sites or based on their content.

Remember that Google is vigilant about fraud. If you inflate page views or clicks, your account may be suspended. Or worse, you could be sued.

Affiliate programs are also ideal for blogs. Amazon pioneered the idea, and it has grown popular. You've undoubtedly seen links on Web pages that say "become an affiliate" (or associate). Click on the link, and you're given information about advertising opportunities.

These programs typically use a cost-per-action model. Your visitor must click the ad and perform an action on the advertiser's site. Usually, the required action involves buying something.

This requirement is more demanding than cost-per-click or cost-per-thousand advertising. However, you're rewarded handsomely. In some cases, you can make 10 percent of the sale.

Affiliate programs also offer a range of tools. Some ads feature a list of popular products; some are search boxes. Ads are available in various shapes and sizes.

You also can opt for less-obtrusive techniques. For example, some affiliate programs allow you to use text links. A code embedded in the link identifies your site as the origin of the click. Your readers won't recognize the link is an advertisement.

To find affiliate programs, check such sites as Commission Junction (www.cj.com) or LinkShare (www.linkshare.com). You can use one account on each site to manage ads across as many sites as you like.

Before you get started, here's some advice. Keep your visitors in mind. Choose ads that offer value to your readers. They'll appreciate it, and that means more money for you.