One of the limitations of translation memory systems is that the smallest translation units currently accessible are aligned sentential pairs. The authors propose an example-based machine translation system which uses a 'phrasal lexicon' in addition to the aligned sentences. These phrases are extracted from the Penn Treebank using the Marker Hypothesis as a constraint on segmentation. They are then translated by three on-line machine translation (MT) systems, and a number of linguistic resources are automatically constructed which are used in the translation of new input. The authors perform two experiments on test sets of sentences and noun phrases to demonstrate the effectiveness of the system. Where the quality of resulting translations is compromised as a result, the authors use a novel, post hoc validation procedure via the World Wide Web to correct imperfect translations prior to their being output to the user.