How to promote website use Twitter?

The main way is:
+ You build relationships
+ Add people up
+ Build either a following or follow someones twits.

Then you earn from finding job or freelance opportunities that you will not find quickly enough or in time via normal methods. And you can also get insider info on prospective jobs and prospects. When you see someone twit: "Having a hard time with so and so ..." you can start offering your services cheap!
Some people blurt out job requirements - so that helps too. Someone upgrades to 4Gb RAM and you know you can get 2 1Gb sticks cheap! Tama ba?