Yes you can but your mom is a right on lady. I'm a paralegal and I think it's extremely important to comprehend all the nuances of the libel law before publishing anything. I have published a post on this called "Libel: Blogging Rights and Wrongs" and you will find advice in it under the section titled "Some take it or leave it advice for bloggers".
While it’s true that we are all entitled to make ‘fair comment on any issue of public interest’, the legal rule of thumb is: ‘fair comment’ must reflect an honestly held opinion based upon proven fact and must not be motivated by malice’.
Also common knowledge and common sense ought to come into play. When it comes to "proven facts," do you have a licensed laboratory for testing beauty salon products that will meet scientific standards equivalent to those of the corporations whose products you may want to critique? If not then you will be relying on the least reliable evidence of all ie. anecdotal evidence.
Consider also that corporations have legal firms on retainer. They take any matters that affect their products and corporate reputation negatively very seriously and can launch a suit against you that takes years to resolve. Moreover, even if you 'win' the suit years later you will have lost your valuable time and money marching off to court over and over again and paying your lawyer to appear with you at every court date, even if the case is simply adjourned again, and gain, and again. Even if the court award through a counter claim goes in your favor by the lion's share of any award you get will go to your lawyer, and you will never regain the hours you lost from work.
So if you think you can get a free blog that free hosted and let fly and damage the reputation of any corporation and their products -- please think again about what your mom has said. She's not paranoid. She's practical and if you are underage, then she's the one who would have to foot the bill and pay the price for any libel you commit.
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