Post-Steroid?

Interesting stat showing how baseball is evolving:

"At the height of the steroid era, in 2001, a total of two pitchers posted ERAs under 3.00. Right now, 25 starters have ERAs under 3.00." ... Buster Olney

I like this trend but I can't help but wonder how these pitchers are cheating to get these inflated ERA numbers.