The threads you see about raising borates is a theory that some are trying that says if your borates are at 50 (adding Borax is how you raise borates), then you use less chlorine to maintain the same sanitation, since the borate level apparently has some anti-algecidal properties. High borate levels are also though to stop the creeping up of pH in pools that have a SWG. The people who are raising borates are adding Borax, then adding muriatic acid to compensate for the rise in pH, so the borate level rises but the pH stays within normal levels. You can read more about the Borate theories here..
http://www.poolforum.com/pf2/showthread.php?t=4712.