  Removing or extracting the commentary sections from a series of websites is a
tedious task, as no standard way to code them is widely adopted. This operation
is thus very rarely performed. In this paper, we show that these commentary
sections can induce significant biases in the analyses, especially in the case
of controversial Highlights $\bullet$ Commentary sections can induce biases in
the analysis of websites' contents $\bullet$ Analyzing these sections can be
interesting per se. $\bullet$ We illustrate these points using a corpus of
anti-vaccine websites. $\bullet$ We provide guidelines to remove or extract
these sections.
