Blacher will combine developing the marketing strategy of Channel 4's mobile, broadband and internet business with promoting new media across all Channel 4 marketing campaigns in her new role.
Blacher was appointed head of marketing at MSN in 2003 after three years working in the marketing department.
She was responsible for high-profile campaigns such as implementing a global tie-up with the release of 'Bridget Jones' Diary' and helping to organise the biggest webcast to date, 'Madonna Live on the Internet'.
Previously, Blacher spent two years working in the Five press office, as well as stints in press and publicity and the marketing departments at Channel 4. She has also worked for the Edinburgh International TV Festival.
Andy Taylor, managing director of Channel 4 new media, said: "Tracy joins Channel 4 at an exciting time as we begin to significantly expand our broadband, mobile and public service activities.
"New media is set to play a critical role in the future growth of Channel 4 and I am delighted to hire someone of Tracy's calibre to help us meet the challenges that lie ahead."
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