I suspect there's a meaning behind the "Best Match" designation. It likely ties in with "Sponsored Listings" or seller ratings, at least on some level. There's probably some data-driven model with a "likelihood of conversion" rating or something similar. Long story short - the "best match" is the match most likely to make money for the platform.
And yes, it seems like they're always tinkering with things. Again, they're likely do this with an eye towards maximizing profits. That, at least, makes sense to me. I can't say I agree with all their decisions; however, I "get it" on a large scale.
With regard to the search function, I think I've got that figured out. The average online shopper has a dreadfully short attention span. They're also somewhat impulsive with their purchase decisions. So, it follows that:
- Truly dedicated shoppers will work through a sub-optimal search engine to find what they're looking for
- The other 99% will see something they didn't know they wanted until we showed it to them.