Here's a hint:

Yahoo does many things right:

    * Yahoo's home page has an average download time of 3.0 seconds according to the Keynote performance index. This is one of the fastest download times among major websites, even though it is still three times slower than required for optimal hypertext usability.
    * The page design is a model of minimalist design: plain and simple HTML that will render correctly in even the oldest browser.
    * Based on hypertext with links, links, and more links everywhere you turn.
    * Leveraging the connected nature of the Web and the many other sites rather than trying to do everything themselves. Yahoo's city guides are a prime example: they link to the best local content in each city - richer than anything that could be built from scratch.
    * Highly structured navigation system that emphasizes context and a hierarchical information architecture (not that hierarchies are the only possible information architecture, but they are easy to understand and represent in the interface).
    * Integration between search and navigation: when you search, the hits are shown relative to their location in the topic hierarchy.

Some design critics say that Yahoo is boring, but the simplicity has its own elegance, even if it doesn't win design awards. In fact, design awards are rarely given to those designs that work best in real use.

The real reason Yahoo is so successful is that it embraces the new medium and designs for its strengths rather than fighting its weaknesses. So, since Internet bandwidth is very limited, Yahoo emphasizes a slim design and forgets about emulating television or glossy magazines. Instead, they base their primary service on giving people good links: the fundamental innovation of the Web (and earlier hypertext systems) relative to other media.

because it is a old search engine and no of user is more in other search engine.

it is a old search engine and no of user is more in other search engine.

If Yahoo is good then you might conclude that Google is better as what I've just mentioned in my comment a while ago. Feel free to see my comment: http://realestateforum.ws/yahoo/yahoo_vs_google-t31.0.html