It's funny that the article (http://augmentingcognition.com/ltm.html) displayed on polars feature page has this:

"I now believe memory of the basics is often the single largest barrier to understanding. If you have a system such as Anki for overcoming that barrier, then you will find it much, much easier to read into new fields."

Also I just made an account to say thank you - polar looks awesome. I just wanted to start using anki and stumbled upon it.