- Spam - Spam is any form of comment that has nothing to do with the subject of the article or the comments that are already present, and promotes something the author is working for or runs. That doesn't just apply to obvious commercial pursuits - spam can be about religion, a political cause, or the commenter's own blog or other written product.
- Pointless insults - A pointless insult is what the words say, an insult that is not backed up by either facts or reasons. For instance, just calling me an idiot is a pointless insult. If you think my mental skills are deficient, explain what information caused you to draw that conclusion.
Better yet, you could simply explain what you think is wrong with what was written.
I don't subscribe to the FireDogLake policy of completely disallowing insults, because sometimes that just means that subtle insults remain while the responses don't. I don't favor them as a form of discourse, and if you do it here you'd better be prepared to back it up with some reason.
- Pretending to be someone you're not - This category covers both sock puppetry - pretending to be multiple individuals when you're actually just one, and just pretending to be someone other than who you are.
- Long quotes from an article - I hesitate to write "don't quote an entire post" or some such, because there are at least two wrong connotations to draw, which is that if the article is really short it can't be quoted, and that if just a little of the article is missing then the quote is OK. Neither is true. If the article is more than a paragraph or two, quote a particularly important or profound part and provide a link.
I should also add, as a caution, that Blogger/Blogspot has a character count limit for comments, so that's another reason to keep your thoughts brief, even if you're not quoting an article. I'm not sure what the character count is, but if you've typed more than a couple of pages worth, it's probably time to stop, and consider starting a blog of your own.
- Proper attribution In keeping with the previous rule, don't pretend you're quoting your thoughts when they're actually someone else's. This is both good manners and keeps us from running afoul of copyright law.
Violation of the first three rules will result in the comment in question being deleted like the intellectual soap bubble it is.
Violation of the last two rules will result in the article being deleted, with a request that the commenter re-submit the comment in proper form, or with it being summarized in a comment of my own, with an appropriate link when possible.
The request may come in e-mail, if I can figure out who you are and where your e-mail is, or in a response to that comment in the same article thread.
Second, just about anything of relevance is not only allowed, but encouraged. I don't mind corrections or disagreements. In fact, I want the former, and am usually glad to entertain the latter. You don't need to ask permission to do either, provided you can follow the rules.
The best thing about blogging, as opposed to more traditional forms of discourse, is the possibility of immediate, verifiable response. So, if you see something that is factually wrong in an article here, or something with which you disagree for considered reasons, by all means let me know.