You can quantify a firm's market power by asking how much the firm could raise prices while the customers would stick with it. If raising the price one cent causes all your customers to abandon you, then you have zero market power. If you can raise prices 10x and sell just as much product, then you have total market power.

https://en.wikipedia.org/wiki/Market_power#Elasticity_of_dem...

For a free product, the analogy to "raising prices" would be "adding annoyances or other negatives to the product".