DVD writers are not all that different from CD writers, so most of the terminology and knowledge associated with DVD writing should be familiar to anyone who has done CD writing before.
Recordable DVDs, unlike recordable CDs, have two different main usages. One, like recordable CDs, if for data storage. The other is for audio and video storage (in the form of DVD-Video and DVD-Audio).
There are actually three different standards for DVD recordables, DVD-R/RW, DVD+R/RW and DVD-RAM. All three different formats come in the 4.7 GB (single sided, single layer : DVD-5) format, although DVD-RAM come in double sided form factor (DVD-9). DVD-RAM is the only format that requires a cartridge/caddy, which means that many drives are not able to read this format. More information about the different DVD recordable standards can be found on the next page.
DVD devices (including DVD-ROM drives and DVD video players) will playback DVD recordable discs, although different devices will have different abilities in terms of reading. The three different formats also makes things more complicated, since the different standards also have different compatibility problems (for example, a DVD video player may read one format, but not the other). Support for DVD re-writable discs are usually rarer than for write-once discs. More information about compatibility issues can be found on this page.
Many first generation DVD recorders did not support CD-R/RW writing, or used smaller 3.9 GB media. New generation drives pretty much all support CD-R/RW writing (although usually at lower speeds than dedicated CD-R/RW writers).