There are a lot of Government Web sites that have made the data that they collect and compile freely available to the public. The licenses that data has been released under are described on the following Pages:
ODC Public Domain Dedication and License (PDDL) Open Data Commons Open Database License (ODbL) Open Data Commons Attribution License
If you are considering starting a project using that kind of data, you should read the Open Data Handbook, which provides a lot in the way of details, and much more information is available on Data.gov, including a broad overview of different types of topics that data is available about, including:
Science & Research.
There’s some interesting discussion of Licensing, openness of data, and attribution in a blog post from the Open Knowledge Blog, titled Open Data: Openness and Licensing.
Below is a creative commons Image from Flickr. In the Caption to the photo is the kind of attribution that a Creative Commons Attribution License calls for when using an image like this from Flickr:
When you choose to use a photo or data available under a Creative Commons’ License, you’re giving other people information about their rights to use your copyrighted materials. This means that you should understand what the different licenses mean
Notice that the information on these sites provides Open Data available through licenses that allow people to create something new or useful
I’ve shared links to and information about the Open licenses that data there has been published under below, so that the information can be shared and it can help encourage others to create using Linked Data, and to share data under Open data licenses like the ones described..