Just like facebook, twitter is another social networking tool that is great for marketing. The main difference between facebook and twitter, is that facebook requires time to build a relationship with your customer, as with twitter, it is mainly to share ideas and to get be straightforward when promoting your company since it only allows a 140 character status. Also, twitter is much more easy to keep updated. In twitter you dont have to be updating a whole page, just a status.
Another function that twitter can have is of a search engine. People are twitter about everything. Even hollywood stars and important politicians are promoting their campaigns through twitter.
Recently, Twitter is now opened to paid advertising. This provides users to have their posts lead the search results. Being able to expose your business through ads is key to success.
Besides marketing, it is essential to share ideas and to see what others think about your company. What makes twitter a must, is that it is easy to use and does not require time to update. Remember time is money.