Tweak introduction

Signed-off-by: Carl Gieringer <78054+carlgieringer@users.noreply.github.com>

howdju-docs/pages/introduction.mdx

@@ -38,17 +38,12 @@ But can we do better? I think we can.
 ## How Howdju helps
 
 Howdju is a prototype of a platform for crowdsourcing and sharing fact checks.
-It lets you store and share your fact checking analysis, allowing others to
-discover, evaluate, and contribute to your analysis.
+It lets you store and share your fact checking analysis, deduplicating the
+effort required to fact check claims. It allows others to discover, evaluate,
+and contribute to your analysis.
 
-Howdju's [mission](/principles#mission) is to to minimize the time required to
-understand representative viewpoints about uncertain or disputed topics by
-connecting users with the most relevant and authoritative sources for those
-viewpoints.
+Howdju users can:
 
-Howdju users have these opportunities:
-
-* Use a purpose built platform to efficiently track claims and evidence.
 * Share their fact check in a structured way online so that their friends or
   colleagues can view, respond, and contribute to their fact checks.
 * Get specific structured feedback on the validity of your fact check from wide