If you post on papers on your ~home/ page it is fine, but if you give your papers to a third party which operates a for profit website then it is not the same.
I am generally not a big fan of Elsevier, but in this case I am totally with them on the matter.
I am actually not a fan of academia.edu, they seem like the scribd/slideshare of academic research. They are another paywall speedbump in the free exchange if ideas. Whenever I hit their page I immediately look for another source.
If they had been more like stackoverflow and less like experts exchange ... but they are not.
If you post on papers on your ~home/ page it is fine, but if you give your papers to a third party which operates a for profit website then it is not the same.
I am generally not a big fan of Elsevier, but in this case I am totally with them on the matter.