Launched in 1999, EverQuest still retains its influential status over a scene that has since spawned World of Warcraft.

Swapping the isometric viewpoint of previous kingpin Ultima Online for a modern 3D camera, EverQuest became hugely popular with Western players -- at least until WoW's rise to power started in 2004.

In March, a month which marks EverQuest's thirteenth anniversary, the MMO will roll out a three-tiered membership structure that allows for free access, albeit on a limited basis.

Gold members can continue to make use of a subscriber arrangement, with the greatest access to characters, abilities, and perks.

Silver members see their access restricted in terms of character choice and progression, while those choosing to play for free are subject to the greatest limitations -- but nonetheless can still roam through all but the most recent of EverQuest's 18 expansion packs.

It's an approach adopted by many MMOs, from licensed properties like Star Trek Online, Lord of the Rings Online and Star Wars: Clone Wars Adventures to original IPs such as Vindictus, Might and Magic: Heroes Kingdoms and City of Heroes.

World of Warcraft added a free Starter Edition in June 2011, allowing player characters to progress up to level 20 (roughly 15 hours' worth), while Guild Wars and the upcoming Guild Wars 2 circumvent subscription issues entirely by asking for no more than the game's cover price.