Final answer:
Local communities use modern technology to preserve traditions mainly through creating online cultural archives, which serve as digital platforms for cultural preservation and engagement.
Step-by-step explanation:
Among the options provided, the case that represents local communities using modern technology to preserve and revise their traditions is B) Creating online cultural archives. Such digital repositories allow for the documentation and sharing of cultural practices, histories, art, language, and more, thereby helping to preserve these elements for future generations. This modern approach supplements traditional methods and provides a platform for communities to access and engage with their heritage in new and interactive ways.