The invention of the compact camera in 20th century gave people a portable and fairly cost-effective way to capture and preserve memorable parts of their lives. With the meteoric rise of the smartphone and current ubiquity of social networking, people now have more ways to highlight and share these unforgettable moments.
The relative ease of documenting oneself has led to the rise of the selfie on social media, and it doesn't look like the phenomenon will simmer down any time soon.