I have a 3 static sites and 1 blog. Since I started 16 months ago I have grossed whopping $215 from these sites. In addition I have some clickbank and commission junction ads and to date have zero sales.
Can it be real money? Maybe for some, but you need to invest real money into the site's marketing to be successful. Often, this is never discussed. If you have an interest in something then by all means go for it. It can be a great learning experience.
This post on entrepreneurs journey sums up my feelings on adsense/adwords.
Why A Preeminent Business Is Superior To Money Making Opportunities » Internet Business Blog | Entrepreneurs-Journey.com - by Yaro Starak
Will I continue with it, not sure. It's a good feeling to have "a" source of cash flowing in. However it won't be anything I can live off of for some time, if ever. It's easy to get your hopes up on a two dollar day or a one dollar click.