Welcome to Miiverse! Marty has announced new update for web version of Miiverse.
First, the position of community search box is moved to the top of the community list. And second, now you can search for users in the web version. Previously, you could only search from your Wii U and 3DS version of Miiverse. The user search box is placed at the top of the activity feed. You may look forward into this change in both Wii U and 3DS version soon.