When it comes to advertising on the Web, it seems that everyone is fighting for space on the homepage. The idea being that there is no better place to advertise - since the homepage is commonly the most accessed page in any Web site and it appears early in an interaction, when anything is possible.
But there are many arguments to make that a simple placement on a homepage is not a good long-term strategy.
First off, there is the issue of context. On a homepage the user has not yet established their intent and thus an out of context ad might not pay off. There is no better example of this than Google. They took this concept to its most extreme - a single text entry form homepage devoid of any other advertising. But Google more than makes up for this after the user has disclosed their context. Once a keyword or phrase is entered - let the advertising begin!
Secondly, there is the issue of timing. In the early days of the Web, there was a concept that users visit Web sites for the fun of it. So a simple homepage advertisement could be the very thing to entice the user. But these days most Web site visitors come with an intent. The homepage is scanned to find the intended target and, once it is found, the user clicks off the homepage. Once they are gone, the homepage advantage is gone with it.
My preference would be to become more ingrained in the navigation of a site. Take, for example, All Recipes. Our Create-a-Cookbook appears in the global navigation of their site AND there is a button placed at the top of each members' Recipe Box. Both the context and timing are right.
Don't get me wrong - given the option to advertise a product on someone's homepage, I'll jump at the chance. But if it becomes the only placement in a Web site, I'd ask for a recount! Especially when considering a product like SharedBook - which is at its best when it is incorporated into our clients' sites.