Now where did I put my ten foot barge poll as I need it for this ;)
To answer your question
NO it isn't legal, just a money making scam
From what I can see Full software download isn't a "site" at all just a paid for P2P client.
If the software makers want to sue you for copyright infringement, they will.
Just remember all the law suits currently running from the RIAA and MPAA.
How Not To Get Sued By The RIAA For File-Sharing
Make sure there are no potentially infringing files in your shared folder
OK so this is a no brainer
I was going to rip your linked article to shreds, but as the WHOLE thing is so much BS I won't bother.
At the end of the day if you use any P2P clients and you have copyrighted material (of any sort) you leave yourself open to being sued.
The mentioned steps are complete cobblers, if the RIAA really wants you then you'd better have an extremely good lawyer as you'll need it.