.useful is Open Source under the Apache license which means you can use it with your commercial or non-commercial applications. The only requirement is to place a note that your software includes .useful.
The Software License (based on Apache Software License, Version 1.1)
Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:
- Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
- Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
- The end-user documentation included with the redistribution,
if any, must include the following acknowledgment:
"This product includes software developed by .useful community."
Alternately, this acknowledgment may appear in the software itself, if and wherever such third-party acknowledgments normally appear.
- The names "dot-useful" and "Denis Krukovsky" must not be used to endorse or promote products derived from this software without prior written permission. For written permission, please contact dkrukovsky at yahoo.com.
- Products derived from this software may not be called "useful", nor may "useful" appear in their name, without prior written permission of Denis Krukovsky.
THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL DOTUSEFUL COMMUNITY OR ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.