Probably a UTF-8 <-> Windows Mixup. Naming Items local with non-latin characters ( ö, ä ,ü e.g.) are saved normal.
When naming them in online Game, item gets Placeholder in Name.
Environment
Client under Win7 64bit, Server under Ubuntu Kernel 3.0.0-15-server
Linked issues
Comments 2
Duplicate of MC-178.
What do you mean "in online game"? Do you mean the minecraft game playable in web browser?