Do user-generated content and votes count as personal data under the General Data Protection Regulation (GDPR)?
For example, on Stack Exchange, do the questions, answers, comments, messages and votes count as personal data?
Posts on social networks are explicitly called out as personal data.
Under GDPR Personal Data is any Data that either on its own (e.g. a photograph) or when cross-referenced with other Data enables to univocally identify one given natural person.
If user generated content allows the identification and/ or Profiling of that natural person then... Yes.
At least for the platform such "link" between the person and the information/ Data is direct... so YES.