What's that again?

What is the difference between DVD-R and DVD+R?

DVD-R and DVD-RW
DVD-R was the first DVD recording format released that was compatible with standalone DVD Players.
DVD-R is a non-rewriteable format and it is compatible with about 93% of all DVD Players and most DVD-ROMs.
DVD-RW is a rewriteable format and it is compatible with about 80% of all DVD Players and most DVD-ROMs.
DVD-R and DVD-RW supports single side 4.37 computer GB* DVDs(called DVD-5) and double sided 8.75 computer GB* DVDs(called DVD-10).
These formats are supported by DVDForum.

DVD+R and DVD+RW
DVD+R is a non-rewritable format and it is compatible with about 89% of all DVD Players and most DVD-ROMs.
DVD+RW is a rewritable format and is compatible with about 79% of all DVD Players and most DVD-ROMs.
DVD+R and DVD+RW supports single side 4.37 computer GB* DVDs(called DVD-5) and double side 8.75 computer GB* DVDs(called DVD-10).
These formats are supported by the DVD+RW Alliance.

What the fuck?