YTV (Youth Television) is a Canadian programming network targeted at children, established in 1988. If it had to be compared to an American equivalent, it would be a combination of Nickelodeon and Cartoon Network (incidentally, Canadian versions of both now exist alongside YTV), from which YTV takes a large amount of programming (and indeed, YTV has aired at least one episode of every Nicktoon there is). YTV has had several programming blocks hosted by PJs, or Program Jockeys, who would come in during the credits and do various things such as answering e-mails while introducing the next show.
A staple of any TV watching Canadian kid in The Nineties. The mornings featured an array of programming for younger viewers with tons of interaction from the PJs and many puppet characters who visited or lived in their lavish, treehouse-themed sets. YTV would eventually split off another network from its morning-midday programming, Treehouse TV, to cater to toddlers and preschoolers. Come afternoon, YTV was the go-to source for everything from Re Boot and Beasties to Sailor Moon, Pokémon, The Secret World of Alex Mack and The New Addams Family, hosted by a duo of wiseass male PJs and their gum-covered alien television creature Snit, whose screen was a giant mouth. Evenings shifted to a darker note with programming such as Animorphs, Cybersix, Are You Afraid of the Dark?, and Goosebumps. Between shows throughout the day, animated shorts dubbed "Short Circuitz" would air, ranging from funny and lighthearted ones earlier in the day to darker and surprisingly wistful ones at night {"Windows", for example). It was also responsible for original and often low-budget shows as well, such as PJ Katie's Farm and Radio Active. These days, most of this material is famed for its massive nostalgia factor among natives of the 1990s and late 1980s. Late at night during this period, BritComs such as Yes Minister and Are You Being Served were run. Early programming also included classic Canadian shows such as You Can't Do That on Television and The Littlest Hobo plus acquired international programming from The Muppet Show to Bonanza.
Come the new millennium, YTV gradually shifted its programming. The network had been an early primary source of Anime for a great many English-speaking Canadians (though non-commercial educational channels like Ontario's TVO and French-language networks such as Radio-Canada and TVA had aired anime as early as the late 1970s). Mapletown had been part of the inaugural YTV lineup in 1988 and the channel later aired a number of shows for younger viewers like Samurai Pizza Cats and The Littl' Bits that were generally thought more as standard kids' shows than as anime. YTV's anime era reached its peak with Inuyasha and the Bionix block, that brought several anime series (mostly dubbed by The Ocean Group for CanCon, or Canadian content, reasons) to viewers. (Many of the earlier anime dubs aired by YTV over the years were made in Montreal or (in Sailor Moon's case) Toronto, which allowed them also to count as Canadian content.) Bionix - best described as YTV's answer to Toonami - also threw in Canadian-produced CGI favorites by Mainframe Entertainment, such as Beasties, Re Boot and Shadow Raiders. The Bionix block was moved to late Saturday nights to make room for reality shows and sitcoms. Before, in 2007, YTV acquired approval from the CRTC to launch an anime-focused channel to be called the Anime Channel. The license expired in January of 2010 and it wasn't even launched.
Although YTV has had live-action shows before, they seem to be more on the rise as of late, with an emphasis on reality shows like The Next Star, Ghost Trackers and The Adrenaline Project. Unfortunately, it appears that they have removed most of their anime lineup to make room for it; some time ago they shortened their Bionix block to an hour of Naruto and an hour of Bleach, but removed the block altogether during reruns. They still show other anime series, however, but mainly ones aimed more at children (Pokémon, Beyblade Metal Fusion). Hopefully they'll acquire the rights to some new anime series soon.
YTV's oldest rival is Family Channel (no relation to the former name of the U.S. network now known as Freeform), which began in 1988 as Canada's equivalent of Disney Channel. Le Canal Famille provided (and still does, though now known as VRAK) additional competition for French-Canadian kids. YTV's biggest modern-day rival, though, is Teletoon.
Not to be confused with Yomiuri TV, a Japanese TV channel in Osaka (affiliated with the Nippon TV (NTV) network) sharing the same initials (albeit in lowercase). Though considering this site's demographic, it's highly unlikely that you will confound them. Incidentally, the Japanese ytv was the original channel for two anime series aired on the Canadian YTV: the megahit Inuyasha and the less successful Case Closed.