From Mefi Wiki
On MetaFilter, each post and comment is signed with a nickname. That comes when you register with the site and login. Nicknames should be chosen carefully, since Matt Haughey doesn't really like changing them (because identity is important in a community). MeFi profile pages can also be referenced by name instead of user number as:
http://www.metafilter.com/username/(the person's name)
For example: [http://www.metafilter.com/username/mathowie]. This can be used to find a user's profile when you only know their name. Profile pages are marked with the "noindex" and "nofollow" attributes which means they are not indexed by spiders such as Google, and any links found on them are not followed by the spider to prevent SEO gaming.
In 2003, Matt Haughey began adding a Gold Star to certain user names at his discretion. Then changed his mind and removed them shortly thereafter.