Collaborative editing of a document

Disclosed is a method, apparatus and computer program for a first client to facilitate collaborative editing of a document with a second client. The document contains data of a first data type and is accessible by a first application for processing the first data type. The first application is used to identify a portion of the document for review, The identified portion is extracted and provided to an application for processing data of a second type at the first client. This application is a messaging application. A second client is identified for performing the review and the identified portion is sent via the messaging application to the identified second client. Comments are received back from the identified second client and these comments conform to the messaging application's protocol. The comments are then interpreted back at the first client and the document is updated if appropriate.