Hi @tylr, I should have written “great post” to you as well, because it was good. Having said that, you got my vote which is the same thing.
I am not sure if we will ever clean steemit of useless spam-comments. It reminds me of the early 1990s when we were trying to stop spam email. There comes a point when the tide is just too big to build a wall.
Don’t worry you risked nothing by writing “Great comment”. Whilst some people might not see the joke, I do - or ignore it if in doubt. I also always look at history to determine if it is habitual spam or a genuine sentiment.
As for a guide, I anm not sure which if any is supposed to be the definitive one. Hovever, doing a search for “etiquette on steemit” will bring up many guides and discussions. There is more than one opinion as to what is acceptable or not - a good example is people who post Twitter-like links to external news stories without original thought or commentary. If you read the discussions, you will get a good feel of what most people think.