A site intended mostly for information dissemination purposes would be one where Shades of Gray schemes ought to be considered. On-line manuals and other reference material also benefit from these schemes. Dark Colors are very powerful and draw one's interest inward. Sites which have a powerful message to convey can safely use these schemes without concern that the message will be misconstrued. Dark Colors can also be used to draw one's attention to something which might otherwise be ignored.
Patterns are akin to wallpaper.
Although one can paint a wall a color and create a mood or solicit a reaction, wallpaper goes that one extra mile to enable one to sustain a mood with color but provide distinction in addition. Use the Patterns schemes for the same purpose. The patterns are in warm and cool colors but also provide a level of distinction not possible with just colors. Use this for sites which are somewhat unique to further distinguish the site from others. Impact schemes are very powerful visually and make a strong statement.