Though game companies have reserved the right to shut down servers when they become a financial burden, the announcement made by Sega and EA to scuttle online play for several games may have gamers reevaluating the value of used games.
Servers for Chromehounds went down today after an announcement made by Sega a month ago. Without online gameplay, the value of of the game may drop precipitously. EA announced it would drop online support for 20 of its sports titles including Madden '09 in April, eight months after its release in August. A full list of EA server shutdowns can be found here.
How this will affect markets for resale and retail may affect how companies regulate servers. Knowing a game could lose half or more of its functionality could affect retail sales while driving up rentals. It could also do the exact opposite and force gamers to buy a game on release in order to maximize gaming time.