Are your non-paying players valuable?
http://gamasutra.com/blogs/BalazsJuhasz/20140530/218719/Are_your_nonpaying_players_valuable.php
“The greatest value of the free riders is keeping the paid users entertained”
“. . . a paid user should always have benefits compared to being a non paying one. Even if you sell just personalizing items to your players, they still need the non paying ones to have someone to compare themselves to and feel themselves unique that they made that purchase.”
Is the same true for Dota 2? I think to a certain extent. Dota 2 does not give an advantage to players who purchase cosmetic items. The Dota 2 community is vocally against any items that are added to the game that could potentially give the player that purchases that item an advantage. Valve is keen to the thoughts of the community and has not put in an item that may shift the balance of game play. However, players who do have cosmetic items can stand out from other players and at times other players may even notice one’s rare item and comment about it. The cosmetics in Dota 2 do create a unique experience for the player who may purchase them. What makes Dota 2 and other Valve games like Team Fortress 2 and Counter Strike unique is that non-paying players can still get item drops in the game. However, there are some items that can only be purchased to get, thus separating the paying users from the non-paying users.
Video Games Shaping Player Interaction 