I think ethics are really important when it comes to blogging. This is because blogs are often directed by one person’s individual opinion. The important thing to do is ensure your opinion cannot be taken as derogative or hurtful.
This means being considerate of others and not defaming someone’s character or a religion, gender, sexuality, race, etc.
If you do, you must take personal responsibility for it and understand that there can be repercussions. In the case of cyberbullying or slander, these could be legal. However, legalities shouldn’t scare you out of it, you shouldn’t really be doing it in the first place.
If you are taking on a negative argument make sure that you are backed up by facts. No one appreciates a blogger spreading accusations without evidence.
Lastly, be original. Don’t steal content, it’s not cool. If you do make sure you have permission and credit the author or the content is licensed under creative commons.
Safe blogging, stay ethical.