Hacker News on 23 September 2007

• 7 reasons I switched back to PHP after 2 years on Rails - O'Reilly Ruby
• Guide to Low Cost, High-Impact Websites
• Wolfram On Hunting For Our Universe
• Photo Story: The Days Before the Xobni Launch
• What every programmer should know about memory, Part 1
• The Unwinding of the Asian Currency Crisis
• What Languages Fix
• Ask news.YC: For the lisp experts - tell me how you learned the language.
• Error Detection In The Gray Matter: Have Scientists Discovered Intuition?
• Paul Buchheit Affiliated imo.im Seeks Hacker ($25k starting bonus)