Dare triumphed in a pitch against undisclosed agencies. It has been briefed to develop online work to support the existing television campaign, created by Miles Calcraft Briginshaw Duffy.
Dare will be charged with translating elements of the campaign for electronic media and driving internet users to ThomsonLocal.com.
Mark Collier, the managing director at Dare, said: "We are delighted to be working with Thomson. It is a genuine challenger brand with a strong consumer proposition and we look forward to communicating this across the internet."
The TV ads broke earlier this month on national TV. The £4 million drive aims to position the directory service as a slicker alternative to its larger rivals.
Thomson's appointments of MCBD and Dare are part of a renewed push to increase the brand's share of the £700 million UK directories market.
The company decided it needed to raise the brand's profile in the face of a cluttered market following the break-up of directory enquiries and the launch of several operators.