system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why do internal search engines often do not work as you expect them to work?
gpt
Because building search algorithms that work *as you expect* is extremely hard. Google works so well because they invested unfathomable amounts of money into the development of their most-known core product, the search engine. Now just compare it to the next competitor, Microsoft's Bing search. While developing that one also took lots and lots of money, its results are arguably worse than Google's, at least in public opinion. So we easily see that, while the amount of spent money on development is still huge in absolute numbers, search quality decreases faster than the money involved. Fast forward now, skip a lot of search engines in between until you're looking at your internal search engine, that probably isn't a core product of a multi-billion dollar company. It's probably just a by-product the developers threw onto a specific product to make it look more complete. There cannot be remotely enough "brain power" in there to provide anything more than exact text search with some fuzzy tolerances in matches maybe. In other words, it lacks any *semantic abilities*. But those semantic features are what you *expect* from a search engine and they are simply not available.

// edit: To provide an example for semantic abilities, based on the example from a post further down here: If you type "Star Wars", then returning "star" and "wars" is dumb. Returning "Star Wars"-matches is better, but still not good. If the engine knows that, for example, "Rogue One" is somehow connected to "Star Wars" even though they do not share more letters than the "r", then you have an algorithm that is semantically useful.