The uses of katakana are many and varied, a fact that I was not aware of until my Japanese class began to discuss this subject. Here are some of my thoughts and findings:
On a bag of Haruya kani chips, the katakana expression “カニチップ “ is used. “カニ” is the Japanese equivalent for “crab”. “チップ” reads as “chip”, an English loan word directly converted into katakana. According to various sources, katakana is often used on things such as signs or advertisements in order to place emphasis on a word or phrase – similar to the Western use of italics (“Katakana”). As emphasis, using katakana in this setting makes sense. The simpler, sharper strokes of katakana are much easier to pick out, and make more of an impression to the eye, than the more complicated kanji or rounded hiragana. Since katakana is also generally used for foreign words, the use of katakana here can also boost the company’s reputation among consumers by emphasizing its status as a product that is internationally traded.

Another popular katakana expression is “カラオケ” or “karaoke”. It can be found on signs all over downtown Manhattan (for a more specific example, look to the sign for Duet 48, a karaoke bar in Midtown East, NYC). According to one source, “karaoke” is commonly written in katakana because it is a relatively new word whose kanji form has not yet been formed (Timmermeyer). This makes sense, because karaoke was only introduced around the 1980s (“karaoke”). The word “karaoke” is actually a combination of the Japanese word “kara” meaning empty, and “oke”, a shortened form of the katakana for “orchestra” (“karaoke). Basically, it seems as though “karaoke” was created as a fad, and as it grew more popular, it took on the name meaning “empty orchestra” because it was the easiest way to describe or name it at the time. As of yet, it is written wholly in katakana because a proper kanji character has not yet been assigned to it. I also venture to guess that its worldwide appeal leads it to stick to katakana because of its foreign audience.
Textbook differences:
In class, we were given excerpts from four different textbooks explaining the different writing systems and their uses. They were all fairly short and very general in their descriptions of katakana in particular. They differed slightly in their presentation of the material, mostly due to the amount of lines devoted to katakana.
The shortest descriptions – the most minimal – made sure to mention that katakana employs more angular, simple characters generally used for foreign names and loan words. The more detailed descriptions also mentioned katakana usage for onomatopoeia and emphasis.
I think the short description was the most simplified definition of katakana, meant for the slower beginner language learners. It introduces one use of katakana that can be easily understood, and leaves the more complex usages to be learned as the student advances in his/her language studies. This is comparable to my Japanese class where we learn one use of a hiragana particle at a time, instead of all its purposes at once. The longer descriptions that included onomatopoeia and emphasis usages were more geared towards the advanced language learner, presenting as much information as possible in a general format – perhaps to serve as a reminder for someone who has previously studied the language.
Sources:
"Karaoke." Dictionary.com. < http://dictionary.reference.com/browse/karaoke>
"Katakana." n.d. Wikipedia. <http://en.wikipedia.org/wiki/Katakana>.
Timmermeyer, Kyle. "Writing Japanese Katakana: Characters that Emphasize New and Foreign Words." 23 September 2008. suite101. 1 November 2010 <http://www.suite101.com/content/writing-japanese-katakana-a69894>.