I figure before I should go any further that I clarify a few common terms that you will hear often when talking about anime or manga.
Most importantly, I should define Manga and Anime:
Manga- Japanese comics. Usually aimed at a wider audience than American comics, that do not go on and on and on like American comics and comic book heroes seem to do. Very often end in under 150 chapters, with variable lengths in chapter lengths (I have read chapters that were 20 pages long, and ones that were 80 pages long. Lengths are usually consistent from chapter to chapter, but differ from series to series). Also don't often have coalescing stories within themselves like in the Marvel Universe, but there are exceptions (See "CLAMP-verse").
Anime- Stories that have been animated. Often these have a basis in manga or light novels, but there are just as many that are original stories. These can be aimed at any age group, but is most well-known for having far more mature and in-depth stories than American television companies are willing to animate. In fact, many US companies will license shows that originally aired in Japan, dub them into English, and market them to American youth. See (and these are the American titles) Naruto, Cardcaptors, Mew Mew Power, Zatch Bell, Pokemon, Yu-Gi-Oh!, and a few others)
First off, there are terms referring to what age group/gender an anime or manga is aimed at (please do not take this as a definitive guide as to what you should be reading- manga aimed at males or children can also attract a fair number of female or adult readers, so go by the review and whatever your personal tastes run towards):
Shounen- These anime and manga are aimed at boys, somewhere from the age 16 and under.
Shoujo- These anime and manga are aimed at girls, from around the age 16 and under.
Seinen- Aimed at men over the age of 16.
Josei- Mainly aimed towards women over the age of 16.
These age terms are just guidelines, however- there are plenty of people who enjoy anime or manga that aren't specifically aimed that them! For instance, you'll find plently of Seinen titles on my manga list, but I an most definately not a man. There are also anime and manga made that really could appeal to everyone, but are marketed towards a specific group for whatever reason (like Aria is supposedly mostly for boys, since it's published in a shounen magazine). So it all depends on personal taste!
Then, of course, you have those aimed at the genre of the series:
Mahou Shoujo- Magical Girl, involving girls that have magical/supernatural powers, usually using them to fight evil.
Manhua- Manga from China
Manhwa- Manga from Korea
Mecha- Involves machines, usually in the form of giant fighting robots
Shoujo-ai- Literally translates as "Girl's Love", is a light romance between two girls.
Shounen-ai- Literally translates as "Boy's Love", is a light romance between two boys
Yuri- Involves love between two women
Yaoi- Involves love between two men
Ecchi- Perverted. Some breast-grabbing or something similar, but nothing graphic and no overt sex.
Hentai- Porn. Overt sex. Graphic views of naked bodies. WILL NOT BE REVIEWED BY ME.
OEL- Original English Language. The manga was not published in Japanese, but originally was in English, for audiences that were not Japanese.
And the term "chibi" refers to a small, deformed- though usually not in a bad way- version of a character. Or, when in the text, literally translates to "small".
You'll also hear me refer to the artist/writer of a manga as a "Magaka".
I believe this covers all the bases. I'll update as I come across other terms, or as people ask about them. I think that's all!
