14. Method according to claim 1 , further comprising: receiving a request for retrieving, said request comprising request information for instructing to retrieve certain user provided information; comparing said request information with said meta-information being assigned to said user provided information which is provided by said information history functionality; retrieving said user provided information being assigned to said meta-information which matches said request information; generating a response comprising said retrieved user provided information; and directing transmission of said response.
14. Method according to claim 1 , further comprising: receiving a request for retrieving, said request comprising request information for instructing to retrieve certain user provided information; comparing said request information with said meta-information being assigned to said user provided information which is provided by said information history functionality; retrieving said user provided information being assigned to said meta-information which matches said request information; generating a response comprising said retrieved user provided information; and directing transmission of said response. 16. Method according to claim 14 , wherein said retrieving of said user provided information comprises: evaluating said user provided information being retrieved on the basis of said membership grade values obtained from calendar entries; said membership grade value defining a measure which allows to estimate a reliability for retrieval.