In many Canadian provinces, standard wall outlets are rated at 15 amps and the outlets look like the ones you are used to, with two parallel vertical slots (one larger than the other) and a third round hole for Ground. An outlet for 20 amps (with appropriate wiring in the wall and breaker rating) has the left slot horizontal, instead of vertical. This ensures that you don't try to mix up sockets with devices with different requirements. Although the link may not be obvious (see below), there is another type of outlet used in Canada and elsewhere known as a "split duplex" receptacle, that looks exactly like the ones you are used to. But inside and in the wiring, it's a little different so that each half (top and bottom) is on a separate 15 amp breaker. Thus, you can plug TWO high-power devices (up to 15 amps each, like a toaster and a microwave) into the two halves and they both work just fine. These are required in certain places in a kitchen where you are likely to use many appliances.
In many states of the USA, they have a different solution to this need for plugging in several devices in a kitchen. They use the type of outlet you have pictured, which is designed to allow you to plug in EITHER a 15-amp plug or a 20-amp plug - both will fit. The wall wiring and breaker are rated for 20 amps. BUT both upper and lower halves of the duplex outlet are off the same 20-amp breaker, just like our 15-amp duplex outlets. Thus you CAN plug two high-power appliances into this duplex outlet and they will work IF the total current is less than 20 amps. If it's more than that (say, two 13-amp loads at once), the fuse will blow. Not quite as sure to work as a split duplex 15-amp outlet, but it usually works OK. And since the wiring is really capable of 20 amps anyway, the outlet is configured to allow a proper 20-amp plug and device to be plugged in. The other "weakness" of this compared to the duplex 15-amp system is that you are able to plug a 15-amp device into a circuit protected by a 20-amp breaker, so it is possible for that devices' internal wiring to be overloaded without tripping the breaker. On the other hand, the breaker and wiring for this 20-amp circuit is a bit cheaper, and it consumes one less breaker position in a breaker box.