APIs (Application Programming Interfaces) allow interaction between applications or websites. Most of the current webpages have APIs and sometimes we don’t even notice that.
While having this type of “relationship” among websites,these are being enriched 
with the connection and interaction as the content interlinks and relates seamlessly.
At Kin Lane’s site, 101.apievangelist.com, there is ia huge explanation and analysis of the most commonly used websites back in 2014, which most of them are still part of the daily life of a tech-average person. He shows these sites have APIs working throughout the whole sites.
What is really interesting is how this analysis at some point may start to be obsolete, since most of the websites/apps that he describes have evolved and been modified already. Take a look at the following picture for example, Instagram back in 2014 compared to nowadays Instagram.
Almost everything has changed in the user interface that Instagram had compared to what it offers right now. Even the font has been tweaked a little.
What’s important about this is that back in 2014 and now in 2016, APIs were used throughout the web without any problem letting users experience a much easier way to interact with others and explore the internet universe.
