I haven't checked the site, but I agree with Haggis that Australia and Britain both have tablespoons which are equivalent to 4 teaspoons. We also have dessertspoons, which are equivalent to 2 teaspoons (half a tablespoon).
I never bother about the difference when measuring.
What does bother me is that conversion sites don't take into account the 'rounding' factor. Who's going to measure out 3.12345 grams of something, for heaven's sake?!? This might be very satisfactory for a mathematician, but for a cook, it's a right PITA, so it just becomes 3 grams, OK? So one ounce translates to 28 point something grams. It's rounded to 30 for convenience.
I was brought up on Imperial measurements, but for 40 years I've been accustomed to metric, and I'm comfortable with both, and for commonly used measurements, I have no difficulty with conversions. Of the two, metric is BY FAR easier to deal with. It is my dream, much like that of Martin Luther King, that one day America will catch up with the rest of the world and go metric!! It would make life much easier for them, as well as for everybody else. For one thing, we wouldn't have to bother with confusing and conflicting conversion tables.
A cup is still a cup. A measuring cup, that is!