1) An ironic expression used by members of the social news site Reddit to bring undue credit to themselves for their involvement in the resolution of a major event, especially when the effectiveness of their crowdsourced efforts stands in dispute.

2) Used after Reddit members manage to collectively shame, shutdown, or exile a person/s from, a group, an organization, etc. with vigilante efforts and virtue signaling.
u/redditanon: Hey Reddit! We've identified the suspects of the Boston Marathon Bombings.
u/redditanon9000: WE DID IT REDDIT!
by CZSPNKr May 4, 2020
Get the We did it Reddit! mug.