The Allowed HTML tags made available to content authors by default in the Limit allowed HTML tags input filter used in the default Filtered HTML text format is a bit too limited. For example, if we want to let people add images, headlines, or superscript text, we need to add the tags that make these possible: img, h1 through h6, and sup.

Here is an example of an expanded allowed tags list

TODO: Look into / mention security concerns with img tag?

TODO: Recommend against including h1?

TODO: Create a module or install profile to automatically expands the allowed tags list so that this need not be done manually on every site.