What search engines don't like

Search engines now know of this technique and define it as "Spam". Currently, sites that use invisible text are banned from most of the major search engines.

The following techniques are Spam:

Meta refresh tags
Invisible text and overuse of tiny text
Irrelevant keywords in the title and meta tags
Excessive repetition of keywords
Overuse of mirror sites (same sites that point to different URLs)
Submitting too many pages in one day
Identical or nearly identical pages
Submitting to an inappropriate category (for directories)