One thing that could help new users dive into Less Wrong would be to make some reading recommendations based on reading difficulty. (I'm including some things not hosted on LessWrong.com when they're very LessWrong-ish and written by leading LessWrong authors.) For example:
For everyone
- Yudkowsky, Harry Potter and the Methods of Rationality
- Yudkowsky, Twelve Virtues of Rationality
- Yvain, The Worst Argument in the World
- Yudkowsky, Reductionism
- Lukeprog, How to Beat Procrastination
- Yudkowsky, Technical Explanation of Technical Explanation
- Yudkowsky, Timeless Causality
- Yudkowsky, Bell's Theorem
It means "I want to become happier", a la "tsuyoku naritai" meaning "I want to become stronger".
The analogue is clever and clear, however I don't think it carries the same cultural connotations. 強くなりたい is a somewhat commonly expressed phrase, whereas 嬉しくなりたい sounds just as odd in Japanese as it does in English.
Perhaps Nancy meant that the title stretches the apropos use of Japanese in evincing the message of an essay written in English.