Are services like codeschool, codecademy, etc. useful?

Question

ruby

It is interesting to read your opinions about such services. How useful are they? At what stage should they be used?
Or is "Practice + books" the best solution?
For me, for example, practice is more interesting. On such services, boring tasks and chew on the essence of the functions briefly and incomprehensibly. All the time you have to go to Google and read. Sense then with service.

Answer 1

I went through HtmlAcademy, and after that I had no desire to get involved with such tutorials.
Inconvenient code editor, tasks like make cats out of a pixel-by-pixel mosaic using only top and left css properties, plus incredible buggy IE 6 on the server to compare the result.
It was not possible to draw anything new, but some kind of practice.