Disclaimer: This is a thought-experiment and I have no intention of releasing any data this way, nor do I have any interesting data to release.
Let's say that a person wants to share data anonymously in a way that people can download the data without it linking back to the source. Let's say the data wasn't illegally obtained, it's not illegal to hold a copy of the data (at least in the US and Europe), the data is of general interest to the public, and it's a modest size (on the order of 1GB).
The typical data-releasing ideas aren't appropriate:
wikileaks wouldn't be interested. Let's say it's not whistle-blower data or anything even close to being controversial.
What are some ways a person can anonymously release data that doesn't track back to the source?