For example, short replies sometimes sound curt or impolite when not intended this way. If you think your words could be perceived negatively, they probably will. Contributions to this online community are valued. In general, you can never send too many messages or answer too many requests for information or contribute too many ideas or opinions. This builds your credibility, encourages others to speak online and promotes your interests.
Common sense is the guide.
You will be perceived as a nuisance. Have something substantive to say. In a way, they are online slang. Used in moderation they can be appropriate. Online discussion forums are generally assumed to consist of personal opinions, albeit informed ones.