Spam has become harder to deal with, as increasingly I find businesses using the comments inappropriately. Industry members are always welcome to participate in discussions. What is not welcome, is for a business to comment incognito in order to endorse themselves or criticise a competitor. I will remove those comments and will not deal with any company that uses such tactics. Comments promoting your business in response to a thematically unrelated post are likewise inappropriate.
Slander refers to posting malicious allegations against industry members and other individuals. (Example: "I heard Company X uses child labor to make their products." Another example: "Hey, I saw that guy beating his wife after the Podunk Brevet.") I cannot host random slander aimed at companies or persons; please take it elsewhere.
Rudeness seems like an obvious enough concept, but it can be a slippery slope. Criticism in itself is not rude. There are also comments meant to be humourous or tongue-in-cheek that can get misread by those who don't get the joke. I consider comments rude when they outright insult others or address them in a bullying tone.
Inflammatory comments are those designed to taunt a specific individual or to provoke a so-called "flame war." I do not always read comments thoroughly, and may not notice these until a full-blown hostile exchange is in progress. In cases like these, I may go back and remove the entire thread, no matter whose started it.
The way I see it, the less moderating I do the better. I hate being in a position of "allowing" versus "not allowing" stuff. Plus I simply have no time to carefully consider the wording of every comment. Long time readers get the benefit of the doubt more so than unknown ones. I use my judgment. Please use yours and mind the moderating rules.