Here is the 2013 edition of the Best of Rationality Quotes collection. (Here is last year's.)

Best of Rationality Quotes 2013 (400kB page, 350 quotes)
and Best of Rationality Quotes 2009-2013 (1600kB page, 1490 quotes)

The page was built by a short script (source code here) from all the LW Rationality Quotes threads so far. (We had such a thread each month since April 2009.) The script collects all comments with karma score 10 or more, and sorts them by score. Replies are not collected, only top-level comments.

As is now usual, I provide various statistics and top-lists based on the data. (Source code for these is also at the above link, see the README.) I added these as comments to the post:

• Top quote contributors by total karma score collected
• Top quote contributors by karma score collected in 2013
• Top quote contributors of 2013 by statistical significance level (See this comment for a description of this metric.)
• Top original authors by number of quotes
• Top original authors by total karma score collected
• Best short quotes 2009-2013

Rationality quotes time! 

The usual rules:

• Please post all quotes separately, so that they can be upvoted or downvoted separately. (If they are strongly related, reply to your own comments. If strongly ordered, then go ahead and post them together.)
• Do not quote yourself.
• Do not quote from Less Wrong itself, HPMoR, Eliezer Yudkowsky, or Robin Hanson. If you'd like to revive an old quote from one of those sources, please do so here.
• No more than 5 quotes per person per monthly thread, please.

Another month has passed and here is a new rationality quotes thread. The usual rules are:

• Please post all quotes separately, so that they can be upvoted or downvoted separately. (If they are strongly related, reply to your own comments. If strongly ordered, then go ahead and post them together.)
• Do not quote yourself.
• Do not quote from Less Wrong itself, HPMoR, Eliezer Yudkowsky, or Robin Hanson. If you'd like to revive an old quote from one of those sources, please do so here.
• No more than 5 quotes per person per monthly thread, please.

Another month has passed and here is a new rationality quotes thread. The usual rules are:

• Please post all quotes separately, so that they can be upvoted or downvoted separately. (If they are strongly related, reply to your own comments. If strongly ordered, then go ahead and post them together.)
• Do not quote yourself.
• Do not quote from Less Wrong itself, HPMoR, Eliezer Yudkowsky, or Robin Hanson. If you'd like to revive an old quote from one of those sources, please do so here.
• No more than 5 quotes per person per monthly thread, please.