Which of the following is not a vendor of web analytics?

OpinionLab is not considered a vendor of web analytics in the traditional sense that the other choices represent. While Google Analytics, WebTrends, and Adobe Analytics provide comprehensive services for monitoring, measuring, and analyzing web traffic and user behavior on websites, OpinionLab focuses primarily on capturing user feedback and insights through methods such as surveys and feedback forms.

This distinction is crucial; web analytics vendors typically offer tools that measure traffic data, user interactions, and provide performance metrics related to user engagement with the website. In contrast, OpinionLab specializes in qualitative data and feedback, which, while valuable, does not align with the core functionalities of web analytics as defined by the other options.