USDT's price is consistently adjusted to be equal to 1 dollar. Users at poloniex.com use this instead of dollars.
How do they make the USDT equal to 1 dollar I wonder?
Are they also used in other places than poloniex.com? Are there other platforms we can trade USDT?
Since Poloniex runs Tether, it is not traded on any other exchange. They peg the price presumably by trading in the right quantities. The reason they made it was so users could save their cryptocurrency profits in a currency which was guaranteed to be stable. (Let's say you left your profits in litecoin and the price went down, you would lose money).
Poloniex doesn't run Tether.