REST API Best practices: Where to put parameters? [closed]

A REST API can have parameters in at least two ways:

1. As part of the URL-path (i.e. /api/resource/parametervalue )
2. As a query argument (i.e. /api/resource?parameter=value )

What is the best practice here? Are there any general guidelines when to use 1 and when to use 2?

Real world example: Twitter uses query parameters for specifying intervals. (http://api.twitter.com/1/statuses/home_timeline.json?since_id=12345&max_id=54321)

Would it be considered better design to put these parameters in the URL path?