It's all changing so fast that I'd be more surprised if you were
able to keep up!
Image verification - also known as "captcha" is a system where you are shown an image of letters, usually distorted, that you have to read and enter into a box. The idea is that a spambot can't read the image, so that they can't do automatic signup in order to spam the board.
We use it on the HUBB for new registrations - you wouldn't have seen it because your registration precedes this version of the HUBB - when you signed up, captchas didn't exist.
Having it on search is a new one on me too! "Why it's there" would be to prevent nasty people from overloading the system with automated searches. Their purpose - DOS - Denial of Service attack - which is simply to bring the server down and deny anyone the use of it.
I don't think anyone hates us that much so have turned it off.
hope that's clear!
Seek, and ye shall find.
Inspiring, Informing and Connecting travellers since 1997!