Out of curiosity--have they been successful with this strategy?
I'm guessing there's some short term revenue gains, and maybe some initial fallout. But the question still stands of whether this works long term. A lot of companies underprice their offering, so this could very well work and an acquisition seems like an ideal time to raise prices while promising more down the line.
Hamachi was a free VPN service most commonly used by gamers. LogMeIn bought Hamachi, and turned it into a paid service, earning the eternal hate of the gaming community.
None of these aspersions are worth considering if you're thinking about enterprise software.