Never heard that term before. What exactly is an idler?
Typically you spend time building a character and equiping them and then send them out on automated quests where you basically go "idle" while you wait for them to come back. Alternatively you watch them do their thing but I believe you don't typically have many actions available to influence the outcome apart from sometimes having a "recall" button to abort the quest.
They are truely insidious. Guess why? An absolute slime ball of a human thought that if the designed games this way they could make people PAY for the quests to finish early!!!!
Another "feature" they normally have is the characters you can choose typically have a rarity i.e. common, uncommon, rare, epic, superhuman etc. These rare characters can typically be earned over a very long period (think years) OR they can be purchased for around 20-50 dollars normally.
The only reason I know is because there are a bunch of Star Trek idlers that people I know play.
Star Trek Timelines:
Imagine paying 50 dollars to get a Captain Picard with a gold border....