I don't think the post was to completely say its pointless to mine, in fact this is the wrong message to send as the network needs miners to work, just don't run down the shops thinking these cards will get you rich quick or at all but the return on investment will be slow or not at all depending on operational costs. But if you have some mining capable hardware why not mine while its on contributing to the network and getting a little something out of it.
I think there is a magic formula to calculate price per mhash based on power consumption / initial purchase cost and each person should do so before raiding the electronics store.
imo buying the 5870/5970/6990 and running it even in a college dorm/office leaves you with 2 problems ignoring the cost of electricity
1) heat
2) noise these things can get bloody noisy, and in fact can become an audible pain in the butt. i'm sure my work colleagues would not appreciate a mining rig under my desk running all day.
However for the more extreme of us and where this blurs between passion and hobby, I'm currently looking at mining using oil based cooling solution, however that ain't cheap either in fact to have a real benefit to offset cooling costs you need to have a large number of cards immersed in the same solution, but is supposedly more efficient than air based cooling although to mine through a hot summer you will still need a good radiator/heat exchanger.
The ultimate goal, is low watt, high hash, low noise, low temps, i have yet to see the solution for all these components.
Meh... I don't think it matters. If we get more miners, great. If we don't, mining will be profitable and established players will expand their capacity. Either way, the network is secured.