The online directories service, Scoot.com, is fighting for survival after announcing the loss of 285 jobs and the resignation of its chief executive.
The company admitted it will run out of money within 12 months unless it makes drastic cutbacks.
Scoot would not confirm which parts of its 1,900-strong workforce would be affected by the cuts.
The most high-profile departure is the chief executive, Robert Bonnier, who will be replaced temporarily by the chairman, Dick Eykel.
But Scoot admitted the radical shake-up, called Project Genesis, might not be enough to save the company.
"The directors recognise there are substantial commercial and implementation risks associated with implementing Project Genesis, of which they believe shareholders should be aware," Scoot said in a statement.
The measures include dropping Scoot's free telephone calls service and removing the three months' free trial for customers placing adverts on the Scoot sites.
The company said the measures would improve cashflow but admitted they would also put off many would-be advertisers.
Scoot's shares nearly halved in value on the news, sending them down to 3.9p. The company was worth £2.5bn at the height of the dot.com boom, but is now worth just £29m.
Scoot was forced to act after its major shareholder, Vivendi Universal, pulled out of takeover talks earlier this month, following the rejection of its £100m offer.
No other buyers have come forward following Vivendi's bid, depite rumours of interest from the French Internet service provider, Wanadoo, and Italy's Thomson Directories.
A Scoot spokesman admitted the company was still up for sale, although the revamp should keep the beleaguered business going until the end of next year.
One option under consideration is mortgaging or selling Loot, Scoot's profitable classified advertising business.
Loot was valued at £177m last year, but is now worth £70m.
MediaGuardian.co.uk special report