Open Data Commons has finally released the Open Database License (ODbL) v1.0 —a major step forward for open data.
Here is an excerpt from the announcement:
The Open Database License (ODbL) is an open license for data and databases which includes explicit attribution and share-alike requirements.
This license, the first of its kind, is a major step forward for open data. There are currently very few licenses available suited to data and databases and none which provide for share-alike (existing share-alike licenses such as the GPL, GFDL and CC By-SA are all unsuitable for data).
The development of the ODbL, has been a major effort extending over more than one and half years with an intensive consultation and review period for the last 6 months.