People generally don’t like security Captchas (I’m on a mission to remove them from this site). And considering my recent experience trying to add a comment to Blogger (ironically responding on a Google post) you can understand why.
Here’s the first Captcha I was asked to solve. What’s that second word?

Nope. No idea. I’ll press that refresh icon and get another one. Ok, what’s that first one?

Thankfully the third attempt was readable. But, really? Google?
And here’s one kindly donated by Dan from Crafted Media…
