A bug is a logo placed on the screen during television programming that identifies the broadcaster. They can range from mostly transparent to opaque, colorful and annoying.

Before the late 90's or so, bugs were used sparingly. They were usually flashed on the screen briefly after a commercial break to let the viewer know what station they were watching. They were also flashed during programming at the top of each hour to do station identification as required by the FCC.

In the late 90's, though, a few television networks started leaving the bugs on all the time. The problem is that so few people complained, stations decided it was okay and continued the practice. Since networks tend to play copy-cat, it is almost impossible to find a television network that does not plaster logos all over its programming these days. Oddly enough, though, the bugs are still always removed during commercials.