Most author websites include the obligatory amazon.com button; a few others process to their publishers. For the most part, the convenience and price are OK; the cut amazon takes from your publisher is a dent in what the publisher will eventually grant you.
But there are other benefits to making your site the point of purchase:
• Money. If you buy a standard of 200 copies from your publisher, expect about a 40% discount. That's decent enough for your website sales to clear a modest profit after S&H costs.
• Audience connects. This is another way for your fans to connect to you direct. Especially for capturing their e-mails for future updates on your next project.
• Popularity proof. The best book promotion for your current book sets up your next book; by showing your publisher the e-mail lists, sales and other direct connects, you're drawing out that much more of the dollars your publisher is willing to spend on the next go-around.
For those of you wary of taking on the hundreds of orders, Mr. Obie Joe advises use of a fulfillment house. One of the best, and willing to scale for a few dozen to more in orders is BCH.