1. A computer method, comprising carrying out operations on a computer, the operations comprising: maintaining machine readable embodiments on a medium of first and second graphs, the first graph comprising a first plurality of nodes corresponding to labeled and unlabeled examples from source and target domains; a second plurality of nodes corresponding to features; and a first plurality of edges connecting the nodes corresponding to the features to the nodes corresponding to the examples according to whether the features appear in the examples or not; the second graph comprising the first plurality of nodes corresponding to the examples; and a second plurality of edges connecting the examples, the edges being associated with indications that indicate whether connected examples are in a same domain or not; deriving labels for at least one target domain based on the first and second graphs; and presenting an embodiment of the labels as a result.