Basically, there are still modders who doesnt follow the standard convention for oredictionary names, registering items/blocks "improperly" causing compatibility issues.
GregTech, since 4.04d (Sep 24th) included a special code to detect those "invalid" entries and suggests fixes for them, although since it is only a particular mod, its range is severely limited, therefore I would like if forge included that feature of GregTech.
Example :
2013-10-19 17:42:23 [iNFO] [sTDERR] WARNING: 'diamondNugget' is an invalid OreDictionary Name. The Name doesn't fit to the Type of Item and/or doesn't follow a proper OreDictionary Convention. If you are the Owner of the Mod who adds this Item, please do the following:
2013-10-19 17:42:23 [iNFO] [sTDERR] Put the 'Nugget' in the beginning of the Name to get 'nuggetDiamond'
2013-10-19 17:42:23 [iNFO] [sTDERR] Private Prefixes could also be a solution if the first Suggestion doesn't apply. In that case the suggestion for the name is 'Translocator:diamondNugget' don't forget to insert the ':' inbetween the Mod ID and OreDict Name, that is the most important part.
2013-10-19 17:42:23 [iNFO] [sTDERR] If you are not the Owner then report it to the Owner of the Mod, which the Item belongs to.
2013-10-19 17:42:23 [iNFO] [sTDERR] WARNING: 'obsidianRod' is an invalid OreDictionary Name. The Name doesn't fit to the Type of Item and/or doesn't follow a proper OreDictionary Convention. If you are the Owner of the Mod who adds this Item, please do the following:
2013-10-19 17:42:23 [iNFO] [sTDERR] Put the 'Rod' in the beginning of the Name to get 'rodObsidian'
2013-10-19 17:42:23 [iNFO] [sTDERR] Private Prefixes could also be a solution if the first Suggestion doesn't apply. In that case the suggestion for the name is 'WR-CBE|Core:obsidianRod' don't forget to insert the ':' inbetween the Mod ID and OreDict Name, that is the most important part.
2013-10-19 17:42:23 [iNFO] [sTDERR] If you are not the Owner then report it to the Owner of the Mod, which the Item belongs to.