ICANN was founded in 1998, when 8 gTLD existed : .com, .edu, .gov, .int, .mil, .net, .org and .arpa.
7 more gTLD were added in 2000 : .aero, .biz, .coop, .info, .museum, .name and .pro
and 6 more in 2004 : .asia, .cat, .jobs, .mobi, .tel, .travel
Some of these gTLD have some innovative business models or uses, such as .tel, who operates in some “template” way. dot travel is restricted in its access to certain number of applicants only. dotbrand are pushing that restriction further, as they closed to anyone that is not the brand.