The big disadvantage is that you wail have to put a lot of time in before you get any returns. the big advantage is that once up and running just keep the writing ticking over and the dosh will trickle in on an ever increasing scale.
The biggest problem you may find is finding which direction to go in blogging money making. there are hundreds of ways of making dosh which way would be best fro you.
If you are a complete novice the best way to make money through blogging is to get your blog site set up and place advertising banners alongside your blog. this is very easy to do and the rewards you get back are commensurate with how much work you put in to getting people to visit your site. This means not only writing blogs but marketing through directories, forums, blogging communities etc.
The good news it that there are many online who can help you, in fact helping people to blog for money is their own business. The problem is there is too much help and you will get side tracked if you're not careful.
The best help for a beginner is Google. They have a complete set of tools, in fact you don't even have to go anywhere else to start earning. It's not a lot of dosh starting from scratch but if you preserve and your traffic increases, so does the dosh.
The beauty about blogging is that your blog subject can be about anything! If you have a hobby or a passion and write about that, it will seem more like dosh made out of something you love to do. Not many money earning enterprises can say that.
If you want to check out the business side of this Google Adsense is your man!