The UK's advertising watchdog has waded into the debate over what exactly constitutes broadband.
Broadband can come in various speeds and with download caps
The Advertising Standards Association (ASA) ruled that net provider Wanadoo could not use the phrase "full speed" in ads for its 512Kbps service.
The watchdog said it would mislead consumers into thinking this was the fastest internet connection available.
The term broadband is widely used to cover a range of connection speeds which are faster than dial-up.
"This is indicative that broadband isn't a single thing any more," Jupiter research analyst, Ian Fogg, told BBC News Online.
"Moving forward, consumers will have to appreciate there will be different types of broadband."
The initial complaint with the ASA was lodged by rival broadband providers, BT Group and Telewest. They both offer a range of faster services.
They said that press ads by Wanadoo, offering "full speed broadband for just £17.99 a month", were misleading as faster speeds were available.
For its part, Wanadoo disputed this interpretation of the words "full speed". It said 512Kbps was widely accepted as the starting speed for broadband.
Instead it accused rival providers of confusing consumers by promoting services with speeds of 150kbps or 256kbps as broadband.
But in its ruling, the ASA said that consumers would think "full speed" meant the maximum broadband speed available.
It told Wanadoo, which changed its name from Freeserve earlier this year, to drop the phrasing from its ads.
There have been growing concerns over the lack of an accepted definition for broadband.
In the UK, providers are fiercely competing for customers, offering both cheap and super-fast connections described as broadband.
"The only common theme is that it is much faster than dial-up," said Mr Fogg. "Broadband is a useful term to differentiate between a slow speed service, which is intermittent, frustrating to use and isn't always on.
"Consumers will have to appreciate there will be different types of broadband.
"This means there is more choice and there is potentially more confusion," he warned.
More than half of homes in the UK are online, with a third of those enjoying a broadband connection, according to a recent report by the communications watchdog, Ofcom.
It predicted that high-speed net connections will surpass five million by next month.