Broadband-based internet TV, also known under the rather unwieldy name of internet protocol television (IPTV), continues to be one of the most talked about topics in consumer electronics, particularly because it combines the gigantic sectors of broadcasting, telecoms and computing.

Companies in these sectors have invested large sums to make the home viewing experience more interactive and personalised, but it's still early days.

Numerous services are available now, from established players such as Apple's iTunes Store , to start-ups such as Joost (currently in Beta). Various programme makers and channels also provide their own video-on-demand (VoD) services.

Channel 4's 4oD is a leading example, but this doesn't necessarily mean that those programmes won't also appear on other VoD platforms, such as Virgin Media 's cable network or BT Vision 's ADSL broadband service.

Like many revolutionary next generation services, initial take-up by consumers has been slow, partly because the public at large is generally still getting its head around broadband, digital TV and personal video recorders. There is also a subscription fee comparable to Sky's monthly charges and, in some cases, hardware that needs to be bought and installed to act as a bridge between your broadband modem and your TV. Simpler services can be accessed purely on a PC.

IPTV technology suits the likes of Virgin, BT and now Sky, which have the means to provide phone, internet and TV services in bundled deals.

Orange eyeing the bandwagon

Orange is expected to follow with a UK service later in 2007. After a soft launch towards the end of 2006, BT Vision is reported to have acquired about 5,000 users to date. This low figure represents, on one hand, the uphill battle that IPTV has to gain user acceptance. On the other, by restricting its service to its own broadband customers, BT is surely limiting its impact. Nevertheless, BT's target is for the service to have gained between 2m and 3m customers within three to four years.

However, content deals for the various IPTV providers are being announced almost daily in both Europe and the US (which as usual is slightly further ahead). Joost has recently made a deal with Guinness World Records to provide 35 hours of original TV programming, joining the likes of Viacom, Endemol and Alliance Atlantis. Meanwhile, Home Box Office (makers of The Sopranos and Curb Your Enthusiasm) are providing 60 hours of programmes to Tiscali 's subscription VoD service, formerly known as HomeChoice.

The BBC announced a link-up to provide limited content to YouTube recently, although it may first need to be approved by the BBC Trust, its governing body. The much more elaborate iPlayer, the BBC's own subscription-free interactive IPTV operation, is set for a summer launch, though again, it has been the subject of public consultations and evaluations from the BBC Trust and the industry regulator Ofcom .

In contrast, Azureus Inc has already launched its Vuze service in the US, which includes BBC and Showtime programmes in high definition.

Once the IPTV propositions get more enticing, then subscribers will inevitably follow. US market researcher iSuppli forecasts that IPTV will reach 103m homes worldwide by 2011 (from less than 4m in 2006). Of that total, it claims that Europe will be the biggest market, with 47m users.

Industry journal Screen Digest makes similar predictions, suggesting that in the UK, IPTV subscribers will jump from just 80,000 at the end of 2006 to 300,000 by the end of 2007, which is likely to be the fastest growth in any European country.