This paper presents some results on lexicon-based classification of sentiment polarity in web reviews of products written in Brazilian Portuguese. They represent a first step towards a robust opinion miner from reviews of technology products. The evaluation shows the performance of 3 different sentiment lexicons combined with simple strategies. It is also discussed the risk of considering the rating provided by the writers for the purpose of evaluating the algorithms. The results\ud
show that the better combination is the version of the algorithm that deals also with negation and intensification and uses the sentiment lexicon Sentilex. The average F-measure achieved 0.73.Samsung Eletrônica da Amazônia Ltda
