I'm not kidding, read the other articles, at least the "Strategy" ones. Some technical details have changed but many of the fundamental principles still apply ;-)
"The pattern of “commoditizing your complement”, an alternative to vertical integration, where companies seek to secure a chokepoint or quasi-monopoly in products composed of many necessary & sufficient layers by dominating one layer while fostering so much competition in another layer above or below its layer that no competing monopolist can emerge, prices are driven down to marginal costs elsewhere in the stack, total price drops & increases demand, and the majority of the consumer surplus of the final product can be diverted to the quasi-monopolist."
Usually, the more competition there is in a market segment, the lesser the margin becomes.
Let's say your customer often "complement" your offer A with B from another company. If the other company faces fierce competition on the market for B, its margin will be low. So, you may be able to capture a little bit more of the customer's money: he wants to spend x on both stuff, the less it spends on B, the more it can spend on A.
It should be required reading for anyone working in anything software related, these days :-)
Heck, read all of Joel's blog when you have time.