Hi Kathleen3,
Welcome to the Mattress Forum! 
While I appreciate you posting here on the forum, the link you shared isn’t specific to the questions placed by the original poster, and the information doesn’t provide much if anything that would help to educate an individual when shopping for a mattress. While the link is bordering on being promotional (which would be against the rules of the forum), I’m leaving it up as there is some interesting chiropractic information contained within that blog, which would be much more useful than the generic mattress information presented.
A more appropriate link for learning how to shop for a mattress would be our own mattress shopping tutorial.
Thanks again!
Phoenix