version of clicking the Like button online is not documented in the User manual, and there only a somewhat-cryptic one-liner mention of it in the Owner's manual, and in the Enterprize group section no less, which most folks don't read:
Disable +1 Functionality
Select this checkbox to disable the automatic conversion of +1 email messages to likes.
Many folks have no idea the feature exists (meself included up to only a few months ago). Here's the latest instance this was mentioned:
A small paragraph about it in the User manual could be helpful. Come to think about it, there's even no mention at all of the (online) "Like' functionality itself anywhere in the User manual, so this could be a good opportunity to add Like info somewhere, maybe in the "Working with messages" section.
Thanks and Cheers,