someone who often disagrees with you but who has your best interests at heart. Always rejects violence so cannot be called a terrorist or an anarchist. Generally dies young or never leaves the house (see house arrest).
Syntactically - dissident (which is a noun) has no associated verb stem. You cannot 'dissid'. You can do nothing dissidently - there is no associated adjective. In fact the word exists alone as an island in a sea of semantics. Perhaps this is why the meaning of the word has persisted unchanged for such a long time.
A person for whom exposure to cognitive dissonance has resulted in rational conclusions contrary to the 'official' narrative of history and/or culture. If this dissonance becomes great enough, the person will be compelled to start producing new cognitive dissonance, becoming a cognitive dissident.
An activist who disseminates information aimed at changing peoples opinions regarding an immoral status-quo could be regarded as a cognitive dissident
The lowest rung on the internet ladder, a Dissent Peddler is someone who plants seeds of destruction among existing internet communities because they stand to benefit from undermining existing leadership hierarchies. They will lie, cheat, manipulate and skew data and make false proclamations that "sound plausible" as best they are able in an effort to put themselves in power. These people are not to be trusted and often work together in small cells, like terrorists, to accomplish their agenda.
Eric and Barbie were the dissent peddlers of the overthrowoperation on that forum. They knew by undermining the leaders with lies, they stood to benefit tremendously.