Why lorem ipsum and not real words
Placeholder text exists so that everyone looking at a mockup judges the design rather than the copy. Put real sentences in a layout and the room starts discussing the wording; put scrambled Latin in and the conversation stays on spacing, hierarchy and type size, which is what the mockup is actually for.
Lorem ipsum works better than random characters because its word lengths and sentence rhythms roughly match ordinary English. A paragraph of it wraps, breaks and fills a column the way real copy will, so the layout you approve is the layout you get.
One rule
Take it out before you publish. Placeholder text left on a live page reads as unfinished to visitors, and gives search engines a block of meaningless content to index on a page that should be about something.
Common questions
What is lorem ipsum?
It is scrambled Latin used as placeholder text in design work. Because it is not readable prose, it lets people judge the layout, spacing and typography without being distracted by what the words actually say.
Why not just type random letters instead?
Lorem ipsum has roughly the same distribution of word and sentence lengths as ordinary English text, so a block of it wraps and flows the way real copy will. Random letters do not, which makes the mockup misleading.
Should I ship lorem ipsum in a live site?
No. It is for mockups only. Placeholder text left in a published page looks unfinished to visitors and gives search engines nothing meaningful to index.