we liked it a lot.
Well, there is an online class 1x a week for 1.5 hours. Questions are welcomed. Also, before the class you are to read through the chapter, doing some of the problems to get a general idea of the material.
Message board problems are posted after class to practice the material covered. Any questions about these can be asked on the message board. If you have trouble with the problems, you can also do more of the problems in the textbook.
Challenge sets are due every three weeks. These cover the previous three weeks' material and detailed feedback is given on these.
Yes, they correspond to the textbook. Algebra 1 and Algebra 2 both use the Introduction to Algebra textbook. The classes do move fast, probably faster than most would if using the books at home.