Aside from Topics (Tags page) searches addressed above there are other ways people locate your content.
The WordPress.com search engine indexes post, pages, and comments content (body text). Unless entered as text in those contents, blog name, post titles, and post/comment author names are not indexed. http://en.support.wordpress.com/wordpresscom-search/
For Google searches use this format and replace "keyword" with whatever word you wish:
Example search string
Queen Victoria site:wordpress.com
results > http://tinyurl.com/csaobsx
Social networking searches for example Twitter search will also be a way that others find your content https://twitter.com/search/
Some will also use Find Friends Who Use WordPress > http://en.blog.wordpress.com/2012/05/01/find-friends/