I missed this post unfortunately when it first came out, but I found a great post from May 6 by Barry Welford about Calls to Action. In his post he lists ten reasons why visitors are missing yours including:

Not Being on RSS News Feeds

Slow Load Time

Too Much Clutter

Unappealing Search Snippet

This article is worth a read as it may cause you to consider your calls to action.

Read the full post here at SEO-Scoop.