What does snip mean in an email?

Answer 1

'Snip', or some more attention-grabbing variant, e.g. >> SNIP <<, means that the chain of previous emails in the current reply has been reduced.

After an email goes back and forth a few times, the original exchanges become less relevant but are often still included in the latest replies. At some point, it is good email etiquette to >SNIP< it :)

Some emailers will diligently >SNIP< on every reply. Some will only do so when they feel that their new reply supersedes previous discussion.

In my opinion, one should definitely >SNIP< away the dead wood of the discussion when copying in new recipients, to clarify their involvement.