Oxfam is using the new medium to encourage people to ask for its white wristband to wear for World Poverty Day on October 17. People can get the wristband by joining Oxfam's current "I'm in" campaign by text or internet.
It is the first time the front cover of a major title has featured a sticky note ad, and required investment in print technology from Guardian Newspapers.
The Observer team is selling the opportunity to use the three-inch square Memostick notes on the front covers of its three other Observer Monthly magazines: Woman, Food and Music.
All Response Media is the first media buyer to take advantage of the medium and in addition to Oxfam it has booked another campaign run for internet phone company Vonage later in October.
Michael Court, deputy managing director of All Response Media who negotiated the deal, said: "This is a wonderful, dynamic idea that as a media first is testament to how innovative The Observer has become.
"The format will be a fantastic mainstay for direct marketing and brand advertisers alike."
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