This is a great video that explains what twitter is... Now, can you use this for your business?  Can you help your website be more prominent on the search engines by using twitter?  Yes.

1 - Follow as many people as you can, friends, coworkers, customers, etc...
2 - Do not copy paste your website link over and over again every 5 minutes...  try to create relationships, promote your business by helping others...  with their problems, etc.
3 - The Goal here is to have MORE FOLLOWERS than people you follow, IF YOU BUILD GOOD RELATIONSHIPS, more and more people will follow your feed.
4 - Promote your services, products and your website at twitter and your followers will convert into potential customers.
5 - Keep in touch, and you'll see you can get business from this and also make your web presence grow.