Selected answers from the Dumb SEO Questions Facebook & G+ community.
Marty Eigner: Can someone recommend a good company (free) which can generate a heatmap for my website?
Greg Baka: I don't think there are any good free ones... We used LuckyOrange for awhile, and I think it was around $10 per month. It provided some interesting results and options.
Jason Nelson: Crazy Egg offers a 90 day free trial - ;http://www.crazyegg.com/wpmu-90-days and then starts billing - https://www.crazyegg.com/pricing. ;It's worth checking out. ;
Dave Elliott: yandex do a free one as part of their metrica analytics stuff. Haven't yet used it personally but others insist it is pretty good
Marty Eigner: It shows you areas of your website where customers are interacting.
Dave Elliott: Basically, its used for checking user experience and how users are consuming your content.
a heat map will show you where your users are clicking on the page and where they are mouse hovering etc. Some of the better ones will follow users(by creating a video) through out their entire journey on the site, so you can see exactly what route they take, what they click on how long they stay there and other things.
Really useful information but a massive rabbit hole to jump down.
Can someone recommend a good company (free) which can generate a heatmap for my website? 
