Leading US TV networks have announced they will provide ratings guidance for parents for entertainment programmes broadcast on the internet.
Fox, CBS, NBC, Telemundo, Univision, ABC and TeleFutura said ratings will appear at the beginning of full-length programmes and online descriptions.
The guidance will be available from 1 December this year.
But broadcasting pressure group the Parents Television Council called timing of the announcement "dubious".
The US Supreme Court is currently considering several cases relating to whether broadcasting restrictions on sexual images, offensive language and violence should be relaxed.
These include a 2002 awards show where singer Cher was heard saying an expletive.
The networks co-signed statement, titled Empowering Parents in the Digital Age, said "the precise means of making the information available will be determined by each company, but the TV ratings will appear at the beginning of full-length video programmes and also in the online programming descriptions".
In its statement, the Parents Television Council said: "Broadcasters have a unique publicly-granted privilege and it is past time for them to start providing real solutions to parents, rather than attempting half measures designed to sway the Court's and the public's opinion."
"This is too big an issue to continue playing games," it added.
However, another parents' pressure group, TV Watch, welcomed the move.
Executive director Jim Dyke said the guidance will give parents "an expanded set of tools to help determine what their children watch, based on their own taste, style and age".
US TV networks have been issuing voluntary notices at the start of programmes on television since 1997 - such as whether they are suitable for all viewers or those over the ages of 14, 17 and older.
But such guidelines have not been available on the web, where many teenagers choose to watch programmes.
A recent study by the TV Parental Guidelines Monitoring Board suggested 61% of US teens were found to watch TV programmes on a laptop, video game player or a device other than a TV set.