Hillary Clinton announces she's running for president in a two-minute video

Hillary Clinton announced her presidential campaign on Sunday with a two-minute video that shows numerous people talking about the challenges they're facing in 2015, including new jobs, new businesses, and new additions to the family.

Clinton then appears and says she has a new challenge as well -- running for president. "Everyday Americans need a champion, and I want to be that champion," she says.

Watch the video below.

Reaction on Twitter has been swift, and varied. Below, a collection of some reactions...