If a website or company is big and famous, should you copy their design for your own site? Likely not, because good UX depends on context, and your situation could be quite different than a world-famous company's circumstances.
Sliding hero images that rotate through a set of promotions, news, or the like on the top of web pages are often annoying to users and are definitely error prone, unless they are designed according to usability guidelines.
No. 1 of the top 10 UX design heuristics is to provide visibility of system status through proper feedback, so that the user knows how commands are being interpreted and what the computer is up to at any time.
Research spanning 20 years proves PDFs are problematic for online reading. Yet they’re still prevalent and users continue to get lost in them. They’re unpleasant to read and navigate and remain unfit for digital-content display.
When deciding which links to click on the web, users choose those with the highest information scent — which is a mix of cues that they get from the link label, the context in which the link is shown, and their prior experiences.
Instructional video content is helpful as supplementary information, though not all users will watch it. Videos should be easily discoverable, consistent in style across the site, and with thumbnails that accurately represent the type of content they provide.