Google blocked WebPosition Gold. According to Google to popular software violated their Terms and Conditions. The dispute is since 2003 when Google penalized website that used to use the software. The last few days SEO managers and webmasters noticed that other automated rank checking applications produced false results.
According to Search Engine Roundtable, “It seems like Google may have implemented a feature that is transparent to searchers but can totally mess up rank checking tools. This is not just impacted WebPosition Gold, but all scraper based tools, including the SEO Firefox plug-in.”