Hit-and-run posting refers to a tactic where a poster at an Internet forum enters, makes a post, only to disappear immediately after. The term comes from the hit-and-run crime on auto vehicles, in which the driver hits another car or person causing an accident and then flees the scene. It is also known as making a "drive-by" posting, a play on the phrase drive-by shooting. The post often consists of a lengthy text making lots of claims that can be, but are not always, on topic.
Another variety is the sole posting of a URL or link that leads to material that might be used as a discussion primer, but with no added opinion of the poster. It differs from plain spam since forum spam often is posted by spambots, while hit-and-run posting on the other hand is done by a real person. Also, while spam mostly consists of advertising, hit-and-run posts usually have at least some bearing on the topic at hand. However, since the poster doesn't stay around to defend the posted material, or even discuss it, it is considered disrespectful, especially by forum regulars who tend to be angered by the fact that the hit-and-run doesn't become obvious until some or several replies already have been made.
Hit-and-run posting often follow the principle of "throw enough in and some will stick", where the poster hopes that even though they will not defend the post, it might at least persuade someone of its merits, although sometimes its motive is plain flamebaiting. Answering hit-and-run postings after they have been diagnosed as such is sometimes considered "feeding the trolls" and is therefore discouraged. Hit-and-run posting tends to occur more frequently in debate on controversial topics.