Here's a comprehensive summary of the Wikipedia article about "Today":
"Today," also known as The Today Show, is an American morning television program that premiered on NBC on January 14, 1952, making it the first of its genre globally and now the fifth longest-running American TV series. Conceived by NBC executive Sylvester “Pat” Weaver and first hosted by Dave Garroway, the show pioneered a groundbreaking format blending national news, interviews, lifestyle segments, and even a chimpanzee mascot, inspiring numerous similar programs worldwide.
Over the decades, "Today" expanded its weekday broadcast from two hours to four and added weekend editions, cementing its influence. The program has largely dominated Nielsen TV ratings, notably holding the top spot for an impressive 852 consecutive weeks until 2012, frequently competing closely with ABC's Good Morning America. Demonstrating continued innovation, NBC launched "Today All Day," a 24-hour digital streaming extension, in 2020.