The default privacy settings of a certain online social networking service are such, that messages posted by a user are visible to their author and to all of her/his contacts, as well as to the contacts of each of her/his contacts. In the set $X$ of users of the service, introduce the relation $\bowtie$ defined as

$$x \bowtie y \Leftrightarrow x \text { can read the posts written by } y \text {, }$$

for any $x$ and $y$ in $X$. Is $₫$ an equivalence relation? If it is, what is the quotient space $X / \bowtie$ ? How can the default privacy settings of the networking service be modified, in order to make it (or make it remain) an equivalence relation? In that case, what is the quotient space $X / \bowtie$ ?