Which are the best online marketing techniques for a service industries like small IT companies?

How can the online marketing methods be classified broadly?
How can a small sized IT company benefit from Online marketing?
What I want to know is that which all methods can be utilized other than having a good website to market the company through online media.

Having a good website alone is no longer enough to create business online.
Assuming your website is there to develo new sales leads and attarcted customers you need to take active measures to drive tarffic to your website.
The basics include key word optimization, search engine optimization and back-link building. Each of these will contribute to your websites traffic.
Also, you can pay to buy key words on search engines so that you can appear as a Sponsored Link in search results, such as the top and side bar results on Google.
Depending on your budget, you can try to do this yourself or you can hire a firm to do this for you.
We discuss a lot of these issues and other ideas at: www.a2mg-blog.com
Feel free to check it out and submit further questions.