These aren't all the thoughts we've had, but it's hard to get Margo to take time away from "her work" -- pattern drafting and handling customer inquiries -- to formally write them down in an essay format. There will be more, though.
For now, we offer you Margo's Confessions of a Former Garb Snark.
In addition, we offer our official policy on copyright and fair usage, and our thoughts on exactly why, in Usage and Copyright of Patterns.