By default, PennTags searches across tags, post titles and post owners. If you want to be more targeted, you can search in each of those fields individually by using the pull down menu beneath the search box. When your search results are returned your search terms will be highlighted in each hit.

At this point, PennTags does not search in the annotation fields. However, by including the phrase site:tags.library.upenn.edu after your search terms in a google search, you limit your results to the penntags site. For example "copyright site:tags.library.upenn.edu" entered into google will return all posts in PennTags that contain the term copyright in the title, tags or annotations.