"Realtor" is actually a genericised trademark for "real estate agent"—one is not supposed to be called a Realtor™ unless they are a member of the National Association of Realtors, which is a trade organisation such agents can join. Of course, this is the country where people will ask with a straight face "What kind of Coke do you want: Pepsi or Mountain Dew?" so good luck getting the masses to follow the suits' lead on that one.
The US publishing industry is also quite anal about ensuring that
realtor is capitalized in novels etc., even if it is not used with the trademark sign.
British English speakers use genericized trademarks too--it is just that the words receiving this treatment are often different.
Hoovering for operating a rotating-brush carpet vacuum cleaner (what Americans typically call
vacuuming) is a classic example. (English Si cites the noun form, but it is the verb/gerund form I have personally seen the most often. I'm not sure it is idiomatic for hard flooring.)
There are some cases where usages fall into sync across the Atlantic and others where they very stubbornly do not. I suspect one example of the latter is the terminology used to refer to taxes on real estate that are designed to support local government. In the US the usual term is
property tax and it is nearly always in reference to what is formally called a millage system. A piece of property has an appraised value; it also has an assessed value that is a percentage of the appraised value that is based on the designated use of the property (different percentages apply to residential, commercial, heavy industrial, etc.); and the levy a taxing district imposes is expressed in mills, one mill being equal to one dollar per thousand of assessed value.
In the UK the policy context is different. For much of the twentieth century property taxes were called
rates and, as in the US currently, was a type of
ad valorem taxation with differentials based on land use. Then the 1980's swung around and Margaret Thatcher shipwrecked her political career by imposing the
community charge, which was informally called the
poll tax because it applied the liability directly to each resident rather than to the property. This was replaced with
council tax, which is currently calculated on a banded system with each property falling in a given band according to its appraised value in a given year and local authorities setting their tax rates as percentages of each band threshold. The UK also sees more widespread use of capping (executed, since the 1980's, by reducing the amount of central government grant a council receives by the amount of revenue it collects above the cap); tax relief on second homes (council tax liability is zero, which causes enormous difficulties in seaside villages where large percentages of the housing is second homes); and tax relief for university students (effectively makes it impossible for a recent graduate to live with students because he or she brings in the council tax liability for the entire property on his or her back, and thus contributes to the formation of student ghettos).
