In addition to these, many people spell their names or other words in an ad hoc manner, irrespective of any system such as the three listed above. For more details, see Wikipedia:Naming conventions (Korean).
Differences between the systems
The first two systems vary mainly in the choice of how to represent certain Hangul letters: both are phonetic systems, and try to represent Korean words as they are pronounced. Thus, the same Hangul letter may be represented by different roman letters, depending on its pronunciation in context. The Yale system, on the other hand, attempts to represent words not as they are pronounced, but as they are spelled. Thus, the same Hangul letter is always represented by the same roman letter, regardless of the Hangul letter's pronunciation.
See also
List of Korea-related topics
External links
Comparison tables of the different systems:
From UN Working Group on Romanization Systems (PDF file) (http://www.eki.ee/wgrs/rom2_ko.pdf)
From a translating firm (http://www.btranslations.com/Resources/romanization/korean.asp)
Korean is agglutinative in its morphology and SOV in its syntax.
Korean is similar to Altaic languages in that they both have the absence of certain grammatical elements, including number, gender, articles, fusional morphology, voice, and relative pronouns (Kim Namkil).
Traditionally, the Korean language has had strong vowel harmony; that is, in pre-modern Korean, as in most Altaic languages, not only did the inflectional and derivational affixes (such as postpositions) change in accordance to the main root vowel, but native words also adhered to vowel harmony.