First, let me state upfront that I definitely do want you to comment here. Please. But I also reserve the right to remove any comment for any reason. Some of the reasons that will almost positively get your comment removed include:
1 - Harrassing other commenters or myself. You can disagree but don't be disagreeable.
2 - Profanity, almost zero tolerance here.
3 - Anonymous comments. I don't allow them, and if you try to post as a moniker, that will probably be removed, even if your comment itself wasn't out of line.
4 - Comments left to posts older than 14 day are moderated and will have to be manually approved. I have this set up because these are the ones that are more likely to get spam comments.
5 - If your comment is clearly an attempt to simply promote your own site, it will probably get deleted. If you leave 'Great post, thanks for sharing!', then five links to your site, it's gone.
The bottom line is if you are respectful of others and leave comments that are valuable to the rest of us, you will be fine. And 99.9% of the comments left here fall into this category. But if you are attempting to attack/flame others, or promote your site, there's almost a 100% chance your comment will be gone immediately. If you have any questions about these guidelines, feel free to email me.