There is one thing that you learn in the psychology 101 “making real surveys” (as supposed to what I call walk-by-washing-powder-survey): DO NOT USE DOUBLE NEGATION. EVER!
Let me show you why:
This is screenshot from a form found on quora.com, a pretty hipp Q&A site version 2.0 with all the social buzz enabled.
Do you understand what the setting actually does? No? Well it’s pretty clear that you can use this setting to have your profile either show or not in the search engines (like Google) – however it is not clear if you need to enable this or disable this in order to show or hide your profile.
That is why it needs a “What?” next to it. Clicking on it brings you here: http://www.quora.com/What-does-enabling-Search-Engine-Privacy-under-Account-Settings-do
WOW! They need that much text to explain a simple setting! (Okay it goes into more depth than just the setting – but that is not my point here…)
Let me explain why you should not use double negation: This requires the brain to make a lot of calculations, because it first needs to access the first negation in order to understand the second one. This is cognitively taxing.
Better would be a dialoge like:
“enable / disable” (change by clicking on it) my profile in search engines
No need to think around the corner here. Now – this is just a setting that I use when I am already a member of the site – worst case: I get pissed off or use the wrong setting. But imagine if you have something like that in your webshop (and trust me: It DOES happen a lot!). People get pissed of and just leave your site – and someone else will make the sale.
Acutally Google recently started rating sites on how easy or difficult the site is to read. Wow! This is great. This feature will increase usabilty for humans (and search engines). And I bet you a free SEO analysis of your website that double negation is a factor of the algorithm used to access use of language on websites. So take care of all your double negations now – before your site get’s a penalty from Google.