In December 2003 when I first startet my online community, it was quite random that the choice fell on Invision Power Board. Later though, I did some research on different community software, looked at pros and cons, and I was still happy with my choice. The forums look and work smooth and are very adaptable. I was able to add paid subscription packages back in 2008. The admin control panel is intuitive to use. And it only gets better. I am happy to pay for the constant development and the support that I can get.