If you are used to write blog posts, wiki pages or even documentation you will endup in a situation that you need to write a code.
It is nice to have you code with color, different font or what ever. Doing it by hand is paintfull, so why not to use a plugin for that? (Ok it is for eclipse).
Are you interested on that? Take a look on Java2Html.
Have you ever asked to yourself if it is really necessary to copy your plugins into the Eclipse diretory and make everything a big mass?
No it is not necessary to make it, take a look on this IBM article: Manage your Eclipse environment, you will be amazed how easy it is to make things organized.