Typically a DVD burner can create both video discs an data discs much like a CD burner can be used to make an audio CD or a backup for a bunch of files.
The difference is that a DVD recorder records a video signal directly into the system and creates a DVD video disc. a DVD burner can do the same, but a DVD authoring package is needed in order to create a compliant DVD. The authoring allows for full menu creation, chapters, linking, etc. whereas a DVD recorder will create simple menus (one for each span of recording) and some basic chapter insertions if you insert while recording.
