Wolfram|Alpha brings much of Mathematica to everyone. It is a wonder of the 21st century, and it greatly helps doing math homework in Algebra, Algebra 2, Trig and more. As a result, grades must be determined by classroom testing and work alone. Online, distance learning in mathematics is more than compromised - it's obliterated, if grading with credit is an outcome.
Consider StudyIsland, one of the best online programs. One student completed the entire course with an A in a matter of a few class periods by placing each question into WolframAlpha - every possible problem. It takes far longer to type a problem such as Solve 3/(x+6) + 2/(x+1) = x/(x^2+7x+6) than to get the answer. Copy the problem yourself, paste it into Wolfram|Alpha and see. The plot is a bit funny, but the answer is clear. Obviously, this would be grand for instruction, but not evaluation.
In short, teach online, but grade in class. Perhaps regional centers for proctored exam taking with video cameras on students and their computer screens will be the next growth industry.