A deck screw differs from other types of screws in that they're stronger and rust resistant. They're coated (usually brown or green) to prevent them from reacting in chemicals in treated wood, paint, stain or water.
High quality stainless steel screws are the best product for decking. Look for the numbers 316 and 305 grade on the box. These are the recommended screw types for building a deck.
Stainless steel deck screws are more expensive than standard metal alloy screws, but provide more protection against stripping or breaking as your deck ages. You may need to replace cheap screws down the line, costing you more money in the long run.
Only Use Deck Screws
Make sure that you only use screws that say "deck screws" on the box. If other screws are used they can react to your wood and cause corrosion problems or even cause stains on your deck surface.
Deck screws can also be used for indoor projects, such as putting up drywall. They can also be used for reattaching siding and putting up mail boxes.