This one is running on PhpBB
Not 10 Mio but still probably the biggest on PhpBB
Gaia has 226927422 articles posted, with 175262033 in storage
We have 1159755 registered users
Most users ever online was 20919 on Mon Nov 15, 2004 8:30 pm
This one has over 5 Million members but it's not PhpBB, looks like a custom software