In December 2003, Square Enix president Yoichi Wada announced that there were over 200,000 subscribers to Final Fantasy XI, allowing the company to break even and start making a profit. Back in April 2009 FFXI hit 2,000,000 active characters. No idea if this considers mules or not. There were between 200,000 and 300,000 active players daily in 2006.As of August 14, 2006 the Xbox 360 version was the sixth most played game on Xbox Live.

Seems FFXI had a slow start but held steady. No idea what the numbers are like now. Still no where near other games which is the saddening part. FFXIV should have been better, damn Square =(