You buying stock constitutes market liquidity. Market liquidity allows companies to do follow-on offerings, buybacks, and preferential rate debt financing (often with stock option collateral) at their leisure. It also allows companies to compensate their employees in stock options - I don't know the best financial term for this, but it creates employee goodwill. Companies periodically restructure their stock option pools (in almost the same dilutive manner as follow-on offerings) so they can continue to offer employees more stock options.