Sometimes, I get newsletters and marketing messages via
email that have everything except a clear call to
action. They're beautifully designed, a joy to read, and
they get me in the mood to do something -- if only I
knew what the sender expects me to do. I don't know
where to click, what link to follow, where to order. --
http://email.about.com/cs/marketingtips/a/et081802.htm
Here's
a list with more information about Call To Action. Check it out.