One of things that self publishing can give you is control, but there are limits to that control, and those limit aren't always obvious. For me, the most obvious example is Amazon's price matching policy. They don't do this for the author or the publisher, they do it for Amazon. They want to sell ebooks that only work on the Kindle, and if someone tries to sell an ebook cheaper somewhere else, Amazon will lower the price without asking--even if it has a different ISBN. No matter what they say, this isn't about being fair to the consumer, it's about staying competitive. It's almost predatory, in my opinion. The only control you have is to not publish with Amazon.
Another example of limits, one which is not so obvious until it happens, is how much control you have over the sites which are distributing your books. I chose Smashwords.com because they provide an amazing service for independent authors. They make it about as easy as it can get to publish a book. They have free formatting guides, and will use that formatted document to automatically convert your book and distribute it to several other ebook stores. They will provide a list of editors and cover artists if you need help, and they will even give you a free ISBN.
The problem is that when the site goes down, you lose control over your entire distribution channel. Smashwords.com has been down for two days now, and I haven't had any control over the ebook stores to which they distribute. I can't even tell them to stop selling my books. This made me realize that, because of all of the drama about piracy these days, the government gets to seize any domain they want, and shut down the site. If, for some reason, they decide to do that with Smashwords, I suspect it would take months to straighten out the mess, and I might not see any of the profit from the sales which occurred while I wasn't in control.
You also don't have any control over your readers. I don't give out one star reviews because if I don't like a book, I don't finish reading it. And if I don't finish reading a book, I don't rate it. Now that I've experienced a bad rating, it seems obvious that not everyone thinks that way. There are people out there who won't like your book, and they won't tell you why. They will read the first page, or the first chapter, and then give it a one star rating. (That makes more sense than reading an entire book which you don't like.) They have that right, and anything you do to try and control them will only make you look like an idiot. I was surprised by a bad rating, but I really shouldn't have been.
You do have a lot of control over advertising. All of it, in fact. What I've discovered though, is that advertising online probably won't be a good return on your investment. I was given a small advertising budget by my web hosting company, so I gave it a try. If I had spent real money, I would have been very very disappointed in the results. Maybe I'll have more to say about that adventure at another time.