As a website owner I get quite a lot of spam emails, usually offering me web design services of all things. These are a bit annoying but what I dislike even more are captchas.
For anyone who does not know what a captcha is you will have come across them on websites which require you to fill in a form. They are usually two unreadable words in a blurry box. You have to attempt to guess what the words are and type them into another box to prove you are in fact a human.
This is the web equivalent of a high street store having a security guard who asks every customer for photographic ID before they are allowed in the shop. It’s going to put a lot of potential customers off and will therefore lose you money!
I will never advise any client to add a captcha to their website, there are other ways of preventing spam which don’t scare people away.