Meaning of "crowded market"

[Sultano]

Here is a pharse in a sentence I would like to know the significance...

" It seemed so unlikely that a paper could be introduced into a crowded market."

[Conchita]

A crowded market is a market full of people.

[Yankee]

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A 'crowded market' can also be an area of business in which there are already a lot of companies doing business (i.e. there is a lot of competition). I think this is what your sentence is referring to.
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[Prezbucky]

AKA industry saturation, market saturation, etc.
_________________
Billie Jean is not my lover. Hee.

[Conchita]

Sultano's sentence makes much more sense now! If you knew the fantastic and implausible spy story I first imagined!