IPT's list management division Holistic will offer the email database to selected third parties from June 1.
In addition, has engaged IPT to build a prospect database of 1.8m 18- to 34-year-olds over the next two years. IPT will use its competition and data capture websites MyOffers.co.uk and WebBrands.co.uk.
Martin Kiersnowski, IPT's chief operating officer, said: "We are absolutely delighted to be partnering with Asos. It has stolen a march in online fashion retailing and is a company that really understands the value and strategic importance of email marketing."
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