Thats not entirely true..
If I have the money to hire a lawyer, I could sue you for looking funny...
Most likely it would be thrown out of court, but the way most companies operate is they outspend their opponets on legals. You're going to spend a heap of money defending yourself, even if you're wrong, and many people will just give up and submit rather than fight.
It happened from a news mailing group abotu pet supplies. Amazing story that shows how screwed up the legal system is in the US. Guy badmouths a store that gave him lousy service on a news mail group, several people agree, store owner files a lawsuit in his home town, next to his office, against people over the internet who are supeoniaed to travel across the country to argue about them criticizing his horrible service. Said people could not afford that battle, and were basiclly forced to pay him damages. Cost to them, on average, 3k a person (8 people I believe). Cost to him. 25$ to file the lawsuit. His son was a lawyer so he got free legal advice.
So, to make a long story short, whether you're charging or not, you can be sued.
Will you? Most likely not, but in the vast realms of possibilty it could happen.
http://www.salon.com/tech/feature/20...quatic_plants/