You may be familiar with the class of collectible trading card games known as 'Trading Card Games'. If not, then consider yourself lucky -- what you are about to read of bears little to no resemblence to most of them. This is, of course, intentional -- it's nothing to do with the fact that I've no idea how they work and couldn't adapt one to the PPC if I did. That's entirely irrelevant.
Putting all that aside! The most important distinction between this game and any other is that you cannot buy the cards anywhere. They're not even being given away. No, in order to, uh, facilitate ease of playing, we have decided to make them available online! All you have to do is pick the cards you wish to add to your deck, download them, and print them out on any paper you choose. What could be simpler? Of course, this means that the rarity markers on the cards are now completely irrelevant, but, well, we can live with that.
In the Third Generation, the idea of Theme Decks was introduced. These are sets of cards (given as a .pdf file to be printed out and cut up) based around a certain theme, which can be used to play a complete game. If these were printed and for-sale cards, they would be "starter decks", or more accurately "two-to-four player starters". But here they're Theme Decks.
The rules, of course, are also available online. They are re-released with every new Generation, and as of the Third, are even further from the original (known as Generation Zero) than they were before. That's just how it goes, I'm afraid.
The cards are made available in .PNG format only, as it is both accepted by Photobucket and not prone to large files or blurring. Similarly, the Rules and Theme Decks are in the .PDF format., as are the tokens you will need to play the game.