mesh won't deform (in pose mode) once parented to bones So I followed this tutorial: riggify to the letter and once I go into pose mode, my mesh will not move/deform with the bones. Only the bones move, without any of the mesh. I have tried parenting to just the bones without the riggify and it still doesn't work. Tried looking up solutions but nothing solves it. 

here's a link to my .blend file: https://drive.google.com/file/d/0B6xONZ2msgKHRDFDaGNJc2RqaWM/edit?usp=sharing 

This link is for AFTER I have applied the parenting (with automatic weights)
Automatic weighting can fail if there's a badly-formed polygons in the mesh. In your case, there are several overlapping vertices in the character's mesh. After executing Remove Doubles on the mesh, automatic weighting works as intended.

As an aside, you're not supposed to use the metarig object as the character's rig. In the Property space > Object Data tab (armature icon) for that object, there's a Generate button that will create a separate full-featured armature object, named rig.



The metarig is provided as an intuitive way for you to indicate where joints, bones, etc. are supposed to be. The script uses the metarig to decide where all the "real" bones and control bones go. That rig object generated from the metarig is meant to be used as the character's armature, not the metarig itself.