Los foros de viajeros constituyen un tipo de encuentro de servicios en forma de ciber-género. Las interacciones entre autor y lector son cruciales para el propósito comunicativo: ofrecer opinión positiva o negativa de viajes, destinos y alojamientos, en respuesta a preguntas concretas formuladas por los propios usuarios. Su objetivo no solo tiene que ver con la persuasión sino también con la evaluación, desde la solidaridad. El resultado es un texto dialógico de dos o varios participantes (White, 2003; Martin & White 2005; Hyland, 2008). Los marcadores interpersonales (Hyland & Tse, 2004; Hyland, 2008) son herramientas que intervienen directamente a través de la voz del autor y del lector para construir este discurso y este tipo de comunicación. Aquí se estudia este fenómeno comunicativo comparando foros de viajeros en inglés y español y extrayendo sus similitudes y diferencias, con objeto de caracterizar este ciber-género desde un punto de vista nuevo, como es el metadiscurso interpersonal.Travelers’ forums constitute one type of service encounter cybergenre where interactions between writer and audience are crucial to gear the text towards its ultimate purpose, i.e. give a positive or negative opinion about trips, destinations and a number of touristic products, as well as answering specific travelers’ queries. Their ultimate goal, then, does not only relate to persuasion but also to evaluation and solidarity, and the resulting dialogic communication can be both diaglossic and heteroglossic (White, 2003; Martin & White 2005; Hyland, 2008), depending on how many voices intervene. Interpersonal markers (Hyland & Tse, 2004; Hyland, 2008) are tools that directly apply to this end and through which the different intervening voices position themselves socially and construe their discourse through stance, engagement, or a blend of both. This is achieved by combining the exposition of factual information with a personal interaction with the intended readers, that in their turn respond, thus creating a diaglossic or heteroglossic discourse. This phenomenon has been analysed by a number of authors (Hunston, 1994; Hyland, 1998, 2004, 2008; Latour & Woolgar, 1979; Skelton, 1997) mostly interested in academic writing. We intend now to explore a radically different discipline, that of tourism in English and Spanish, where the interactional metadiscourse framework has already provided a number of works (Suau Jiménez & Dolón Herrero, 2007; Mapelli, 2008; Suau Jiménez 2012a, 2012b) that have shown relevant cross-cultural differences in the way writer and reader deploy their voices to attain persuasion in promotional genres. The study of travelers’ forums in English and Spanish constitute a new challenge since dialogic engagement is inherent to this genre, with several functions and purposes intertwined –persuasion, solidarity, evaluation-.The expected results are that cross-cultural and cross-linguistic differences between English and Spanish might be confirmed, since metadiscursive interaction is strongly stemmed on socio-linguistic roots. The new generic variable –travelers’ forums- may unveil new uses in the way writer and audience relate through interactional markers to construe their voices and reach persuasion, evaluation and solidarity.