Cybersquatting is the act of registering, trafficking in, or using a domain name of a trademark or business name with the bad faith intent to profit from that activity. Some cybersquatters use close variants of a trademark, which is commonly called "typosquatting." In the late 1990s and early 2000s, cybersquatting was more common than today, because the Internet and company websites were still relatively new. But today, you do still occasionally hear about incidents of cybersquatting. With the expansion of generic top-level domains (gTLDs), the FTC and trademark owners are concerned about a re-emergence of cybersquatting and fraudulent schemes.
I occasionally hear of someone registering a domain name with someone else's trademark in the hope of making money down the road. This is the essence of bad faith intent to profit, which is prohibited by the Anticybersquatting Consumer Protection Act. If you are using a domain name or close variant to complain about a company, consisently with the First Amendment, you may be able to get away with it. But if you are using a domain name with someone else's trademark in order to make money, you likely will not get very far.