Quote Originally Posted by Ultimatecalibur View Post
Horizontal Gear Progression is where gear increases the amount of content you can do without increasing the Character's overall power to much. Currently there are three pieces of content that you might seek to have BiS for: FCoB, i80 PvP and Uncapped PvP. All three have different secondary stat needs and limits. By collecting more gear you can enhance your capabilities in each, but do not grow more powerful. One gear set will not rule them all. If new content was added that needed different gear, but that different gear does not overshadow existing gear then you have horizontal gear progression.
This is also what makes horizontal gear progression so hard to achieve as well though. Many games take a lazy route and simply add a special stat to each gearset that you need to have x amount of in order to survive a specific piece of content. Doing it in this way can actually make it incredibly frustrating for the players because they essentially gain no benefit from the new gear besides meeting an arbitrary requirement that does nothing for their combat abilities.

Done properly, horizontal progression on gear does still improve your combat abilities but by way of versatility and utility instead of power. FFXI is a perfect example of this as many pieces of equipment had effects on them that modified your skills. The result was that changing from one gear set to another caused you to lose some effects and gain others, thus it balanced itself by nature of the effects being mutually exclusive and some content would require you to use certain sets over others. Unfortunately the gear-swapping in FFXI ruined the whole concept as everyone was able to gain the benefit of every set at once but the theory was sound.