A blogwar, also known as blog war, is a coordinated troll movement to intimidate bloggers into shutting down their blog. This is achieved through posting flames and threats on particular entries. Typically, the blog warriors declare blogwar on sites that they deem trite, cliched, or stupid.

One of the shortlived pioneers of this practice was Blogwar which was later shutdown after surviving for only a few months. This site contained a list of targets and a list of successfully shutdown targets. Blogwar managed to force many bloggers to shut down their blogs (primarily on Xanga). However, after many of the successfully shutdown targets had created new sites under different names, and the users generally lost interest, the site was shut down by its owners after its short-lived crusade.