The BBC Trust today said the corporation should cut the costs of its "red button" services by focusing on a narrower output.
It said the interactive service should concentrate on its most successful areas such as news text as well as live sport and music coverage.
More than half the annual £39.3 million spent on red button goes on distribution costs across different platforms.
The Trust review said it was the most used interactive service in the UK, accessed by more than 12 million people each week with a weekly cost per use of 6.4p
But it said costs needed to come down - and audience appreciation could improve.
The Trust suggested costs could be cut by more of a consistent service across all digital platforms, rather than tailor-made services for each.
It should also concentrate on its strengths, rather than aiming to tackle all genres.
The review pointed out that the digital text service with its news, weather and sport updates drew most visitors. And coverage of live events - such as Glastonbury, Formula 1 and the Olympics - were also a hit with viewers.
BBC Trustee Diane Coyle, who led the review, said: "Red Button reaches a large audience and is effective in helping the BBC promote some of its public purposes.
"It is not as popular as the BBC's other interactive services such as the iPlayer, however, and its overall costs - particularly for distribution - are substantial.
"The Trust will therefore look to the BBC Executive to reduce costs when and where possible by focussing on the aspects of the service that are most successful to date."