You can search for content using the Search bar at the very top right of any page. You can specify what user's posts you're looking for, or date parameters for your search.
Click on Members in the main menu to view a list of members with the most messages, likes and points in the community. You can also search for members from this page.
As you may have noticed, below each user's name there are statistics noting the number of messages they've posted, the number of likes they've received, and the number of trophy points they have.
These trophy points are earned based on messages posted and likes received (for example, you might receive a point for every two likes you receive, or for every two messages you post. The points you earn qualify you for new user titles and in some cases, expanded permissions within the forums (such as custom user titles). You'll also receive other trophies that recognize you for your contributions but don't affect your user title (for example, recognition that you have received 50 Likes, have posted 100 messages, etc.)