I have been in the software business for a long time, since long before the web as we know it appeared. One fundamental tenet of that business is Make it easy to buy.
The book publishing business is no different. The big publishers understand that. Amazon and B&N and others understand that. But independent authors often don't. I took a fellow author to task because she had a blog with great content, and even provided an excerpt and talked about her recently published book, but she had no links or way for a reader to buy.
Remember, the reader is asked to part with his or her hard-earned cash, which is a hurdle to overcome even if the book is 99 cents. Don't put up any obstacles. If they have to go to Amazon or Smashwords or B&N and search for your book, especially if the book title is ambiguous or made of common words (Try searching for 'I Wish...' via Google, then try searching for 'Paranormalcy"), they may lose patience before they get there.
The three things that are most important to provide, either directly or indirectly, are a link to where it can be bought (even if you are selling it directly), a cover image (picture is worth a 1000 words) and an indication of genre/age ('Mary, Mary Quite Contrary' could be children's rhymes, YA romcom or horror). The last is sometimes clear from context, which is fine.
If all goes well, in a couple of days, you will see an image and link appear on my blog for Savage Fire. As soon as it is available to pre-order or order, I'll make sure you can see it, get to it and know what it is. Do the same for your book. You don't want a potential reader to skip on by to the next blog because there wasn't a simple way to buy your book.
Trust me. In the software world, it's known as a newbie mistake (although large corporations sometimes make it - not mention names such as IBM or anything). Don't be the newbie with your precious book (or software). Make it easy to buy, and people will.