On Reddit.com there's a recent post with a question about some of the lesser known PHP tricks that other developers might have picked up out there. The post has pulled in quite a few suggestions including:

• Using predefined interfaces
• The streams API
• Defining constant defaults
• The speed differences in reading parts of arrays
• Boolean attribution

There's also a full discussion on closures/lambdas that no "features" post on PHP would be complete without. Have some tips to share? Add yours to the post too!