Talk about it here.
Titan was smaller than Earth, but had a much denser atmosphere. (PROSE: The Wheel of Ice) In fact, Titan's atmosphere was 50% denser than Earth's, but its gravity was only 14% as strong. (COMIC: The Soul Garden) The surface temperature was 200 degrees below 0. The upper atmosphere was rich in tholins, which would rain down on the surface. The surface looked like the barren landscapes of Earth, but with different colours; the black lakes were actually made of liquid methane and ethane, while the red rocks were made from ice. There were icecanoes, which spewed out water and ice. It reminded Jamie McCrimmon of the Land of Fiction.
Though it was believed to be incapable of supporting anything more complex than bacteria, Titan actually had advanced life, such as the massive Titan-sharks that swam through the lakes of methane. (PROSE: The Wheel of Ice)
At one point the Daleks established a colony on Titan. This colony was eventually destroyed when the Daleks drilled too deep and ignited flammable gases beneath Titan's surface. This explosion destroyed the colony and created the rings of Saturn. Traces of their presence were later discovered by human colonists. (PROSE: Dalek Saturn Probe)
In the 21st century, there were a few human colonies harvesting methane on Titan. When the children of Mnemosyne were blamed for the damage caused by the Blue Dolls, some of the teenagers decided to revolt and escape to Titan. Once they got there, tempers flared and accidents happened. When Sam Laws was badly injured, they were forced to call for help and return to Mnemosyne. (PROSE: The Wheel of Ice)
In the 47th century, citizens of Saturn who reached 100 years old were forced to go to Titan, where they ended up doing menial jobs and remotely operating all the public services and amenities on Saturn. (PROSE: Saturn)