You can search for people based on the content in their profiles, very much as you would search for content. This works even better when you and other people add to your profiles information that the rest of the community might be interested in. For example, you could add a list of the things you're skilled at, a list of your interests, and so on.
To find people, click Browse > People. On the People page, enter the terms you want to search for, then click Search People. If you get a lot of results from your search, you can narrow the list further by using the filter options to the right of the list.
When you click the name of someone in the search results list, you can get their profile and a lot more. You also get lists of the person's content, tags they commonly use, and more.