The Elder Scrolls Online cause quite a stir last year when Bethesda Softworks and Zenimax Online Studios announced that the game would charge a subscription fee of $15 per month.

Bethesda and Zenimax have defended the fee in the past. In a guest post on MMORPG.com, Goblinworks (Pathfinder Online) CEO Ryan Dancey explained that MMO subscription fees bring in $100 million/month for western companies. On the other hand, free-to-play games are estimated to bring in half this amount per month - and these games far outnumber their subscription-based counterparts at this point, making the former figure all the more impressive.

"If we consider the MMOs that generate the most revenue in the Western market (North America, Europe, Russia, and Australia / New Zealand) a sizeable majority of the revenue being generated is in the form of monthly subscriptions. The era of MMO subscriber transparency has ended but we can still make some educated deductions about these revenues and subscriber totals."

Zenimax and Bethesda made a list of the highest-grossing MMOs in the West when making the decisions for ESO, and this chart supported their theories that a subscription model would support the game better. The three highest-grossing MMOs in North America - World of Warcraft, Club Penguin, and Wizard101 - all charge a monthly price of some sort.