Although these are high-quality corpora, they have some limitations: (1) they tend to be domain specific (e.g., government related texts); (2) they are available in only a few languages; and (3) sometimes they are not free or there is some restriction for using them.
to measure the quality of the BS Detector, we manually labeled 200 Web sites (100 positive and 100 negative) from the dmoz directory in topics related to Spanish speaking countries.