Much has been made lately of tension between Twitter and its outside developers.  The issues stoking the fire are less legal issues than business issues brought to front-burner by two particular factors:

(1) The maturity of Twitter as a development platform, or in the words of Ryan Sarver of Twitter, “In the early days, all the clients except Twitter.com were built out by ecosystem companies, mainly because Twitter was so focused on keeping the lights on.  But we learned that in order for us to really grow, we had to start taking over that core experience.” (quoted in the NY Times, 7/17/11).

(2) A reported Federal Trade Commission inquiry into the relationship by the , which has (in some views) caused Twitter to re-think its liberal open-door policy when it came to permitting outside development on its platform.

An excellent story and accompanying podcast on this subject appeared in the NY Times last week, written by Claire Cain Miller.

Bottom line: Twitter is seeking to control the applications that control access to Twitter, meaning desktop and mobile, and leaving the field open to enterprise applications, usability applications, analysis and similar applications.

Certainly the business reasons seem pretty clear, in that Twitter seeks to control core functionality – and the development of that core functionality – of the mother ship.  Although it is not terribly surprising that that strikes some critics as cynical, see for example here (“Twitter, just be honest: ‘The only way we can figure out how to make money is same ol’ display ads and we need to own the client for that.’”)

There are legal issues here, namely the ability of the platform to restrict access to its API.  As Claire Miller and others have noted, part of the problem for Twitter is that developer expectations may have been artificially inflated.  But there is more.  The FTC hint of antitrust scrutiny may be causing Twitter some heartburn about its historical open-ness.  Some analogy from two unrelated contexts: In trademark law, the concept “use in commerce” requires confirmation of continued public use of a registered trademark every 5 years or so.  In real property law, a property owner’s failure to restrict public access to property – and thus demonstrate its private claim – can, under some circumstances, support a court’s granting a permanent public right of way.

Quoting Rob Diana from Regular Geek, “Twitter also now owns the platform as a whole and must be as reliable as a utility company.  They must provide all of the capabilities that consumers need in the clients.” (emphasis added) A danger for a “public utility” of the information superhighway is creeping expectation of the duties and obligations of public purpose: Loss of commercial freedom, permanent regulatory scrutiny and public stakeholder claims.  It may very well be that Twitter is acting much like New York’s Rockefeller Center, which closes public access to traffic one day a year as a legal “fiction” in order to continue to assert private ownership rights.

Twitter rolled out its new API TOS (“Developer Rules of the Road”) in March of this year.  Rob Diana noted at that time that the announcement may have been – or perhaps should have been – anticlimactic, in that “A basic Twitter client is a terrible idea in today’s ecosystem.”  Wrote Diana:

Unless there is major functionality outside of the existing solutions, a new client is a losing idea. There is a high barrier to entry when we already have third-party clients like Tweetdeck, Seesmic, HootSuite and PeopleBrowser. This does not include some of the other applications that focus on team or brand management. So, by saying not to develop a new client, Twitter has saved us and investors a lot of time and money.