Is there a good website with paid (subscription or per course) model where you can really learn advances programming skills? Are they worth the money?<p>I found some examples:<p>* Pluralsight
* SitePoint
* Udemy<p>What about free alternatives? Are they (more) useful?<p>Maybe?<p>* MIT Open CoursWare<p>Or any other?<p>Are you using such?<p>Do you have such subscription, maybe provided by your employer?