I am not an attorney and any comments I post are not intended, nor should they be construed, as legal advice. If you need legal advice, please consult a legal expert who is familiar with the area of legal expertise you need.
Updated May 12, 2020: Added the red text to the above disclaimer and added the link to: How to Mostly Remove the Re-blog Option on WordPress – May 12, 2020.
This may sound like an odd question, but the answer is odd. The viewer or reader makes the determination. For the most part, it doesn’t matter although there can be cases where it matters a whole lot. Use of affiliate or referral links can also determine if a blog or website is commercial.
A good example is a re-blog. In this case, where the original blogger is located can make a huge difference. In the U. S., there is a copyright legal concept of “fair use”. Not all countries have fair use so it’s best if you are re-blogging from someone who lives in a different country, you check out if the country’s copyright law has “fair use” or a similar exception. It’s also good to see any legal precedents from the courts in the country and how they ruled on the subject.
I researched a country that has “fair dealing” in place of “fair use”. I read the country’s High Court’s explanation and it was vague in my opinion. Basically, the High Court determined on a case by case basis if it applied.
In the U. S., parody is an exception although it should be clearly marked as parody to reduce the likelihood of getting sued. However, you can still get sued for parody usage and potentially could lose. Best to spend the money on a good copyright attorney before going this route.
I read an American blogger who defines a site as commercial if it has ads on it. Doesn’t matter if you make money off the ads or not. The blogger doesn’t consider “fair use” an exception. I doubt the Supreme Court would agree with the blogger on the point. I choose not to re-blog their posts.
If you don’t want people to re-blog and you have a WordPress blog, you can disable Re-blog. I will do a separate post on it shortly.