Magic: The Gathering isn't always the easiest game to explain to new people. While it's not exactly The Cones of Dunshire, it's no solitaire, either.
In the collectible card game's first five years, there wasn't exactly a learning curve for new players. Those coming in often learned from a friend of theirs who already played, either by word of mouth and/or this fad called the Internet.
By 1997, adoption by younger players or those needing a more simple rule scheme to get up to speed needed a kick, or at least according to Wizards of the Coast. That's where Portal came in.
Portal was a set with simpler rules and a somewhat reduced card number to help bring these players in. Instants, enchantments, and artifacts were non-existent, with creatures being just creatures (as calling them summon spells was considered too complicated for Portal). Terminology was also made more generic, with "library" becoming deck and "graveyard" becoming discard pile.
Rules were also simplified. Basically, it was a watered down version of Magic.
They hyped it up too. Those weird MTV slots? Yup, promoted it there, as well as during other popular shows. Some booster packs were also given for free via mail-in offer to try and get new players in. Wizards of the Coast was seemingly in a rush for new Magic players.
However, a curious thing happened. Rather than Portal getting a ton of new players, a lot of Portal-targeted players went straight into regular Magic: The Gathering. The game did see a tick up in sales and players because of Portal, so it was good on their end, but why was no one really playing it?
Well, first off, Development had no idea what it was really doing. It was codenamed "Harvey", named after the famed invisible rabbit from a Jimmy Stewart movie that was big, there, and invisible.
Why have all these different rules when you wanted to eventually get everyone to Magic? And that's when the second part came in. As it turns out, just because you have simplified rules doesn't mean that everyone will suddenly know how to play.
Portal players went to those who knew Magic, learned the regular Magic rules, applied them to Portal, found them to not be working (at least, not quite the same), then simply just went to the full version of Magic and play it enough to get used to the difficulty.
Essentially, Portal just became an extra step, or at most, catalyst to get to the more organic process - asking friends, family, and fellow Magic lovers at places like game stores to help them through.
Not wanting to to let Portal go, the team tried again the next year with Portal Second Age and, in 1999, again with Portal Three Kingdoms, which was made with eyes on further expanding the game into Asian markets. The company would make a final beginner-level push with Starter, which replaced Portal (albeit briefly before canning it).
Each time, they made it more and more like the rules of traditional Magic: The Gathering to help make learning the new rules easier to switch over. However, new players simply chose to rough it out in normal Magic more often than not. Of course, it didn't help things that Portal-unique cards (that is, the non-reprints) weren't legal in sanctioned play until 2005.
So, in a way, Portal worked out alright -- just not in the way that Wizards of the Coast had hoped.