CamelCase, originally known as WikiWords, and gramatically known as medial capitals, is the archaic term identifying the ability to link to another page on early wikis by removing the space between two (or more) words which began with capital letters. At the time, it was a revolutionary way of thinking of technology — "What is the simplest thing we can do to make this work?" — to paraphrase WardCunningham. CamelCase is very important for 'LinkLanguage' — that is: writing and adding links easily to your writing. Ward has commented that instead of adding ten characters to make a link, he took away one. JohnAbbe pointed out that you have to shift (on the keyboard) for each word capitalized.
Modern wiki syntax
Moving forward into todays' 'wiki world', the MediaWiki wiki engine was developed from UseModWiki; and, because it was developed for an encyclopedia, where proper spelling, word spacing and grammar are of high importance; the use of CamelCase to create internal links was phased out and is deprecated in MediaWiki. In order to create an internal link, one must enclose the wanted link in double square brackets —
[]. This became colloquially known as a 'wikilink', and has now been accepted by all subsequent wiki engines as the de-facto standard of creating internal links.
Likewise, WikiIndex (which also runs on MediaWiki) does not (and can not) use CamelCase to create links. There is, however, some sentiment (and practice) that CamelCase should be used on WikiIndex when creating categories or templates which contain two or more words, such as category:LoginToEdit or template:MultilingualMain. Unfortunately, in some cases, neither convention is consistently followed, even among subcategories of the same category! It may be observed here on WikiIndex that our founding fathers still have an unrelenting favour for the use of CamelCase; whilst to some of the newer, younger WikiIndex folk, CamelCase might seem like a foreign language!
Problems with CamelCase
It should be noticed from the lead paragraph that CamelCase links can only work on written languages based on Roman text, which use upper- (capital) and lower-case letters. Non-Roman texts, such as arabian, indian and asian texts (which don't use capital letters) would not be able to use CamelCase. Another problem with CamelCase, as displayed, is that it can cause inaccuracies, or even failures when using online translators to translate, say English texts using CamelCase into other languages, even those using Roman text. Furthermore, for those wikis which can utilise CamelCase links, the feature will create inadvertent links with phrases that have internal capital letters, such as Paul McCartney (turning his surname into a wikilink).