> I recently received a request to implement the "retweet" api calls in the
> python-twitter and java-twitter libraries, but before I proceed I was hoping
> for a bit of clarification around the licensing terms for the Twitter API.

> My layman's understanding is that without explicit terms there are
> relatively few rights offered by default regarding a specification.  In
> particular, I have a few questions about copyright, trademark, and patents
> rights being offered to implementors of the Twitter API.  My longstanding
> sense is that Twitter has indicated the spirit of offering the API under
> generally permissive usage rights, so hopefully this thread can move the
> discussion forward a bit and perhaps turn that spirit into something more
> formal.

> *Copyright*

> **Question: Under what terms may third-party library and application
> developers use the text and images associated with the Twitter API
> specification?

> Example use case:  Third-party library developers would like to copy and/or
> modify the text of the Twitter API specification in the library's
> documentation.  This is preferred over inventing new text for the
> documentation, the meaning of which could deviate from the canonical version
> in the Twitter API specification.

> Potential concern:  Without a copyright license, implementors may not be
> permitted to use or reuse the Twitter API specification text in third-party
> library documentation.

> Current state:  While the Twitter API specification itself doesn't mention
> copyright, the Twitter Terms of Service (http://twitter.com/tos) state:
> "The Services are protected by copyright, trademark, and other laws of both
> the United States and foreign countries," which could reasonably be
> interpreted to apply to the Twitter API service as well.

> Possible desired outcome:  The Twitter API specification is made available
> under a permissive and derivative works-friendly copyright license, such as
> the Creative Commons BY or BY-SA license.

> *Trademark*

> Question: Under what terms may third-party library and application
> developers use the various registered service marks of Twitter, Inc?

> Example use case:  Third-party library authors would like to use the words
> "twitter", "tweet", "retweet" (all live service marks of Twitter, Inc) in
> their libraries.  This is preferred over third-party library authors
> inventing new terms for API methods such as "retweet".

> Potential concern: Without terms that specify where and how the various
> registered marks can be used, third-party library implementors may or may
> not be permitted to use terms such as "twitter", "tweet", "retweet", etc.,
> in their libraries.

> Current state:  The Twitter Terms of Service (http://twitter.com/tos)
> appear to prohibit such use: "Nothing in the Terms gives you a right to use
> the Twitter name or any of the Twitter trademarks, logos, domain names, and
> other distinctive brand features."

> Possible desired outcome:  Twitter publishes acceptable-use guidelines for
> registered marks in third-party libraries and third-party applications.

> *Patent*

> Question:  Under what terms may third-party library and application
> developers make use of current or future patent claims made by Twitter, Inc?

> Example use cases:  A third-party developer may wish to implement an
> independent service that conforms to the Twitter API method signatures, or a
> third-party developer may wish to implement a library that implements
> portions of the Twitter API on the client.

> Potential concern:  Without terms that specify how third-party developers
> may use patent claims (if any) made by Twitter, Inc, implementors assume the
> risk of potentially infringing on current or future claims made by Twitter.

> Current state:  Twitter (to my knowledge) has made no statement regarding
> patent claims with respect to implementations of the Twitter API.

> Possible desired outcome:  The Twitter API specification is made available
> under a patent agreement, such as the Open Web Foundation Agreement (
> http://openwebfoundation.org/legal/), or a similarly permissive agreement,
> such as the Microsoft Open Specification Promise (
> http://www.microsoft.com/Interop/osp/) or a Google-style patent license (
> http://code.google.com/apis/gdata/patent-license.html).

> ...

> I realize that these are meaty (and potentially legally sensitive)
> questions of course, and likely ones that are not easily answered in a
> public forum.  However, any feedback from the team would certainly be
> appreciated.

> The fact that people are even thinking about these types of questions is a
> good thing, both for open specification development in general, but also
> because it shows how successful and important the Twitter API is today.  So
> again, continued success with the API, and I look forward to hearing more
> from the team.

> -DeWitt