As an example, a few months ago a young developer I worked with implemented a set of attributes on a table as a bit field. He had just read an article about then and did it because it sounded cool. It made running reports against the data and doing imports via plain SQL impossible without writing a bunch of extra functions. His clever solution that saved about $0.0001 worth of disk ended up costing several hours of developer time because he didn't just a join table and a foreign key.
Eh, that needs qualification to make sense. Just crawling and trivially tokenizing the web counts as "indexing all the individual web pages" but that's never been such a monstrous task.
Having results fresh to-the-day/hour/minute is a better example of something that will probably be looked at is child's play even though that's a very new, very computationally expensive development in search.