Blogging is not only about publishing your views and ideas. One can also earn good money by blogging. In fact, these day's kids prefer to blog for pocket money. Basically there is no harm in this because doing so makes them earn money as well get acquainted to various new technologies. Kids' blogging on their topic of interest increase their knowledge base that in future helps them to get good grades.
Advertising Programs : this is one of the most obvious things to do. In this program a blogger is asked to put other companies' advertisement on their blogs, for which they are paid good money. For example, one can earn through most popular program called Ad sense by Google. There are few more along this line like Bidvertiser, eMiniMalls, Chitika's, Text Link Ads, WidgetBucks, Azoogle Ads, Tribal Fusion, Double-Click, Adbrite, Intelli Txt, Value Click, AdHearUs, Kanoodle, Clicksor, Pheedo, Fast click, Text Ads, and BlogAds.
Sponsorship : few companies have directly started their own advertising program. This is done by sponsorship where they find blogs that have good page ranks and offer them good money to advertise for their company. So what you basically need is make your blog good and make an effort to increase its page rank. This can earn you great hassle free money. Two of the companies offering this are Adobe and Ricoh.
Digital Resources : bloggers can acquire few digital products and sell them on internet. For example, e-books, audios of tele-seminars, courses, lesson plans, electronically published articles etc. This can result in a lot of money, but requires a good amount of effort.
Affiliate Programs : there are various affiliate programs like Amazon, Clickbank, Commission Junction and Linkshare that offer great revenue. One doesn't need to do much, just enroll to these affiliate programs and put their links on your blog. Whenever, a visitor signups through your blog you get a share of the revenue.
Blog Writing : bloggers can very well if they have flair for writing. There are many bloggers who don't get time to write and update post on their blogs, but to keep pace with the blogging world they want their blog updated regularly and hire third party bloggers to write for their blogs and pay them accordingly.
Few other opportunities are RSS advertising, blog network opportunities, non blogging writing opportunities, donations, flipping blogs, merchandising, consulting and speaking.