In response to PDC, Pokemon is a overarching brand comprising of a video game franchise, an anime series, and a trading card game along with other smaller spinoffs. With the exceptional creativity of the original ideas as well as the intriguing gameplay of Red and Blue, "pocket monsters" were an instant hit. Ever since, its popularity has only been increasing exponentially.
Primarily, the anime series is a TV show aimed at kids in the 7-12 age bracket. Simple yet elegant animation combined with time tested characters like Pikachu and Ash very appealing to the previously mentioned ages. Personally, I think the quality of the anime is excellent as far as animes go; the graphics are solid, the story is interesting and dramatic, and it can draw from a huge pool of Pokemon for ideas. Also, I've found the Pokemon movies to be wonderful entertainment in that their stories - especially the earlier ones - provide deep morals and ideals much like those presented in the popular Dragon Ball Z series.
Obviously I could discuss to great lengths the competitive nature of the Pokemon video games; however, as an aficionado yourself I'm sure you have sufficient knowledge in this regard. Therefore, I will focus this brief statement on the direct gameplay of the Pokemon games on the handheld consoles. Red and Blue were obviously big hits, but I feel the greatest masterpieces of GameFreak yet are the popular Ruby and Saphire. The completely new storyline is refreshing to old players, and new players are neither overwhelmed or underwhelmed by the exquisite gameplay. As I don't have much personal experience with 4th generation games, all I can say is they don't appear as impressive as the preceding ADV games. Black and White are clearly aimed at a slightly older audience with their more mature story and they seems to be nice games as well. Overall, the battles themselves are very intense and user paced, while the encapsulating story is highly engrossing with intricate plot lines including various villains, gym leaders, and legendary Pokemon.
Hopefully this gave you a basic understanding of Pokemon past the information found in a Pokedex. If you want more information on the Trading Card Game, there are several resources listed just in this forum. For other information, feel free to PM me. Finally, I advise you refrain from posting utterly useless posts with absolutely no truth or meaning behind them.
Edit: Hopefully this resolved the blatant ignorance of teegrun