"Build or buy" refers to the decision making process of whether to "build" a piece of technology or "buy" it. For example, a computer hobbyist may prefer to build a new home PC while a casual consumer would prefer to buy a PC.
Possibly a prelude to the AntiPatternNotInventedHere in SoftwareDevelopment. However, the benefits of building software may exceed the cost of building software. The trick is in knowing if the cost versus benefits comparison favors the "build it" side versus the "buy it" side. Some factors for comparison:
Expanding the groups' expertise base.
Create a uniquely powerful solution specific to the product's market.
Produce a product which is overall superior to the competition because of advanced technology.
No additional licensing costs for deployment.
Investment in new technology support:
Training for staff
Risk out the ying-yang.
Pre-configured solution, requires little effort/time to make it work.
Already known bug free, good, and meets the needs.
Known cost of development and deployment.
Uses possibly staid, tired technology.
Produces a product just like everybody else's, making yours a Me-Too commodity.