The Teen Titans started as a team up of Robin, Kid Flash, and Aqualad in The Brave and the Bold in 1964 (which makes 2014 their 50th anniversary) and later became known as the Teen Titans including Wonder Girl and Speedy. Their adventures were very...groovy and pretty campy as was the fashion of the time.
In the 1970s the Teen Titans became a bit more serious as a sort of junior justice league and had a variety of encounters with super villains as well as increasing their ranks with such heroes as Bumblebee, Bat Girl (Kathy Kane, not Barbara Gordon),Beast Boy, Hawk, Dove, Harlequin etc. The series only lasted 50 ish issues and was cancelled in 1978
In 1980 George Perez and Marv Wolfman rebooted the Teen Titans as the New Teen Titans and featured Robin, Kid Flash. Beast Boy and Wondergirl joined by new characters Starfire, Raven and Cyborg. The new series became a runaway freight train of a success featuring the creation of Deathstroke, Brother Blood, the Hive, and others. New Teen Titans was the number one comic for much of the early 80s and the mature form of storytelling changed comics and led to Wolfman and Perez overseeing the complete reboot of the DC Universe with Crisis on Infinite Earths in 1985.
It was the Wolfman Perez Titans that got turned into an animated series on Cartoon Network and which still lives on (sort of) as Teen Titans Go!. Given how much the current DC TV Universe has mined the Titans for story ideas and villains it only makes sense that they take the next step and incorporate the whole team in their plans which would bring aliens and magic into their already rapidly escalating world of metahumans. Also notable is that unlike many other Team books of its time the Titans heavy hitters were all the women (Starfire, Wondergirl and Raven) and so it makes for an attractive demographic.