Near-invisible UI improvements

The newest issue of EDN magazine had and article explored near-invisible user interface improvements. While a user is spending time with the system, he/she might not mention little modifications done in the background by a team of developers.

"...expert foley (sound effects) is invisible to a movie viewer, until the foley is either missing or implemented poorly." [read it]

That reminds me the words of Mark Zuckerberg, the founder of Facebook, during StartupSchool conference held in March 2007 at Stanford, who have mentioned that they are doing little improvements to the site every day. Small patches of code are constantly added seamlessly improving the user experience.