Ask your average blogger and the answer will be "maybe".
The number one rule in blogging is 'Do not start a blog in hopes to make money'. Because it just won't work. You need to be passionate about something and love what you write about. You need to blog for fun, for an outlet, for joy...blogging for money won't work out.
It takes years to start to earn money through writing a blog, and unless you love what you are writing about, you won't have the followers nor the backing to be able to start to earn an income - your blog needs to take off before your blog becomes noticed in the big circles. Your blog won't take off if you are posting drivel or posting sporadically.
You need good advertisers. It is difficult to find individual sponsors who will advertise on your blog and the pay is often small. Google AdSense is readily available to post to your blog but the payout is slim. It pays per click, so unless you are getting loads of traffic to your blog with one or two clicks on the ad a day it isn't worth it. I've had Google Adsense for close to 2 years now. They don't pay out until you reach $100, which I've done once. My account is at $50 right now do instead of taking the ads off my blog, I will wait until I reach my next $100 payout and then cut ties with them. I've heard of some blogs getting several visitors and clicks on their Google ads and being told that the activity looks suspicious and Google closing their accounts, with the unpaid funds never being seen. That looks suspicious to me!
Unfortunately, the better paying and more prestigious advertising companies have waiting lists a mile long and it's extremely difficult to get your blog approved. One of the biggest known blog advertising groups is Blogher, which I happen to have on this blog. It took over a year after submitting my application for this blog to be approved. It's an excellent circle to be in and the pay is per impression, not advertisement clicks. Most of the top bloggers make their big bucks through Blogher, but you really need a huge readership to make a nice income off your blog. Some bloggers are lucky to make enough to support their family, or even have their husband become a stay-at-home parent just because of their blogging income.
For the average blogger, such as myself, it's not worth it to blog if you are merely blogging for money. I did not start my blog to earn revenue so anything that comes my way is an extra perk and helps my family out. Some months I'll earn $60 from blogging, and some months I'll earn $15. It depends on how much traffic my blogs has (which relates to how often I post) and also depends on the amount of advertisers that Blogher has each month. It's a perk...it's not an income for us.
The biggest perk of blogging, for the average blogger, are the reviews that are offered up. Many companies know that one of the best advertising is not a blatant advertisement, but rather an honest review put out there on the world wide web. Any google search of their product name will bring up the review and many women reading blogs find the reviews to be helpful when choosing a new product to try. Many blog owners, myself included, are showered with items to test out and keep, all for the sake of writing a review and publishing it. It's a nice perk - to be able to try out products before anyone else and to be able to share the product with my readers. I'm careful to only test items that I would be interested in myself and that would fit the demographic of my readers.
Can the average blogger make a decent income from blogging? No. In a world of mommy blogs you are just another fish in the sea. It's good to branch out from "mommy blog" and find your niche, which can bring a bit more awareness to your blog, but unless you are incredibly lucky, it is doubtful that you will become the next Pioneer Woman.
That is not to say that you can't make money from your blog. It is possible, after years of blogging, having a decent readership, getting connected with the right advertising circles that you could make blogging both fun and profitable. There are many blogs that have an income of $200-$500 a month and that's nothing to laugh at. It just takes time and work - which is why starting a blog with the idea of getting rich won't work. You need to love what you write in order to make others love what you write. Whether it is about your own family, saving money, living green, and so on...you need to love writing about it.