Writing good blog posts is a creative process that often requires just right supporting media. While Zemanta tries its best to find semantically most relevant recommendations, it turns out that often only writer knows exactly what metaphor or a specific image is needed to add that extra edge to the post.
That is why we added "filter" option to Zemanta. It allows you to specify a term that Zemanta recommendation engine should take into account while deciding on what's most important in your text. It's not a classical search, since it still takes into account your body of text.
When you enter your term, all recommendations will change. Images will be more focused on your term, as will articles, links and tags.
If you enter a term, that is mentioned in text, Zemanta will try even harder to find a place on Internet to link it to. That's useful if you're sure that something should be hyperlinked, but we didn't automatically figure out that it should be link. After using filter, if we can, we'll provide recommendations for link target.
If you want to disable filtered recommendations and go back to initial ones, just click on Filter again and they'll disappear.
There's also a short screencast that you can take a look, demonstrating usage of Filter feature on adding puppy picture to a blog about cats :)