TV delivered over broadband Internet connections will become increasingly popular in Europe over the next four years, new research has predicted.
The number of subscribers is set to hit 8.7 million in 2009 - up from 658,000 now - giving operators almost 9.5% of the pay-TV market, Screen Digest said.
The leading enthusiasts in Europe are currently viewers in France and Italy.
But the services have taken longer to catch on in the UK, amid competition from satellite and cable firms.
The report into IPTV (internet protocol TV) looked at standard broadcasts and on-demand programming delivered via broadband on normal telephone lines to TV screens.
Europe's telecoms firms are looking to both IPTV and broadband to offset falling income from their traditional fixed-line business - offering a so-called "triple-play" service.
The Screen Digest research suggests IPTV is set to pose a significant challenge to established cable and satellite operators, although they too are starting to invest in the area.
The impact of IPTV is predicted to be strongest in France, Italy and Spain where operators would have between a 16% and 20% share of the pay-TV market by 2009.
London-based Homechoice, which has announced plans to expand beyond the capital, is the UK's leading IPTV service provider.
The market is set to get more crowded next year with new services from BT and other broadband providers.
About 7.5% of pay-TV viewers in the UK could be using IPTV in four years, Screen Digest said.
"Although some technical and content issues have yet to be resolved, the combination of compelling, competitively priced triple-play offers that include true video-on-demand will prove a winning formula," said report author David Schmitt.
"Many traditional pay television providers are finding that they too must adopt IPTV technologies in order to remain competitive."