The I2P proposal, proposed two months ago and currently in commitment phase, appears like a natural subset of the Darknet posposal from one month ago which is currently in its definition phase. So I'd like to know how they relate to one another. Possibilities I can think of:
The two proposals have different focus. Anything that relates specifically to I2P technology should go to the I2P site. Anything that could equally well apply to other overlay networks should go to Darknet, even if in a specific example I2P is the technology being used.
The two proposals are deliberately distinct, and time will tell which community each of them attracts. I2P questions are welcome (at least initially) on both, and posters can decide where they want to post.
If the I2P proposal goes public beta, then I2P-specific questions should be considered off-topic on Darknet, for the same reason Tor questions are off-topic, namely there is a more specific site for them.
If both proposals reach sufficient traction (e.g. reach private beta?), there should be an effort to merge them, making I2P a tag in the Darknet Q&A.