How does my amiibo/card interact with my handheld system?
If you have a New Nintendo 3DS system, you will be able to interact with your amiibo/card by placing it over the bottom screen of the handheld. If you have an older Nintendo 3DS (note the lack of the word New) or a Nintendo 2DS system, you will need the Nintendo 3DS NFC Reader/Writer to interact with your amiibo/card.
The Nintendo 3DS NFC Reader/Writer is a hockey puck shaped accessory that communicates wirelessly via the infrared port of your handheld device. The Nintendo 3DS NFC Reader/Writer will be available for purchase in the fall of 2015.
Were Super Smash Bros. for Nintendo 3DS/Wii U the first games to support amiibo?
Although Pokémon Rumble U was the first game to support the Wii U GamePad's NFC capabilities through interaction with its own line of figurines, Super Smash Bros. for Nintendo 3DS/Wii U were the first games to officially support amiibo figurines.
Are similar character amiibo figurines interchangeable between series?
The short answer is: yes. For example, you can use Super Mario series Yoshi with Super Smash Bros. for Wii U. But keep in mind that this will reset the data already saved on the amiibo. So, if you were using Super Mario series Yoshi with Mario Party 10 and then decide to use that same figurine with Super Smash Bros. for Wii U, the data that was stored on Yoshi from Mario Party 10 will be deleted.
There are more regions than just US and EU. Why are JP and AUS release dates and rarity missing?
You are absolutely right! Integrating data also means keeping it up to date and currently we simply don't have the time or resources to integrate all regions. But rest assured, we aim to be the definitive guide when it comes to all things amiibo. Integrating all regions is on our list of things to do.