Of my many interests as a UX designer is why we change things. Why we incrementally modify interfaces, what drives those changes, etc. I'm sure we've all scratched our heads at an app or service's UI updates, perceiving some as useful and some as "design for design's sake."
Facebook, for me, is one of the more fascinating services out there that seems to straddle the line between meaningful change and change for no reason. They also do an astounding amount of AB testing on features as I'm sure everyone knows. I've seen my wife's app get updates that I never got in mine, and vice-versa. I have no doubt that there's data driving most of these changes and updates, but many leave me baffled as to what, if any, value is derived from seemingly minor cosmetic changes that bring frustration in adapting to them.
A great example: My most recent app update changed the size of text in an expanded comment thread by 1px larger (visible when you click "See more comments" in a lengthier comment thread). In the collapsed view, the font size didn't change. In expanded view, it's larger, and just feels odd. Why did it change only in this context?
The same could be said for past updates that introduced rounded bubbles to contain comments, as a change from what was previously just full-width text and indented replies, as discussed here: https://qz.com/941314/facebooks-new-design-for-comments-shows-they-dont-understand-what-conversations-are/
Like I said above, it's fascinating, yet mind-boggling at times depending on the update. Anyone have some insight into this, or into what drives their incremental changes? Do you feel most of their updates are rooted in purpose and value, or, do you feel that some are "design for design's sake" or change to imply they're keeping things fresh?