As part of the MOSS email features outlined here, a RFC for like via email.
Current behaviour: No way to like a post via email
Proposed behaviour: Clicking on a ‘ this post via email’ link in the email will like the post in question automatically.
If logged in: The user is taken directly to the post in question
If logged in as a different user:
The user is taken to a screen with the post in question, and a notice that they have liked it as the email user.
If logged out:
The user is taken to a screen with the post in question, a notice that they have liked it, and a prompt to log in.