How to create site like yahoo answers

You can easily create a question and answer website on wordpress with "DW Question & Answer" plugin. You can download it from - http://wordpress.org/plugins/dw-question-answer/
Below is a tutorial (video+text) for creating a question-answer website using "DW Question & Answer" plugin.
http://www.wpbeginner.com/plugins/how-to-create-a-question-and-answers-site-in-wordpress/

Question and answer type website are usually called as forum website. Technically it is different from normal website. Forum site allows you to give permission to the user. You can assign few users as editors, normal users and restricted users. Forum sites needs permissions because not everyone are allowed to access all the resource. For example in Yahoo Answers if any user is spamming, editors have rights to delete his/her content. This kind of constraints are not applicable for normal website.

How to build question answer type website?

Lefora is a website which provides you this facility. It has features like popular social network integration, email notification to the user, games, chat facility and automatic spam filters. This website allows you customize the layout of your website. You no need to type any html/java script to customize the layout. You can just use the drag and drop tools available in this website to create a new forum website.

If you want to start a website like Yahoo Answer on Wordpress go through the steps mention below.

1. Install WordPress and Add DW Question Answers Plugin.
2. Activate plugin.
3. After sctivation you will see two new pages has been created by DW Question Answers Plugin in your WordPress Website.
Page 1. DWQA Questions and
Page 2. DWQA Submit Question.
4. Go to pages option on your WordPress Dashboard and Select All Pages.
5. Now click on Quick Edit Link below each link.
6. After editing, click save and get ready for editing user role who will post question and answers on your website.
7. Click on Settings and choose General. Now go to membership section and check box which says anyone can register.
8. Choose subscriber as the new user default role.
9. Now again come to your DW Question Answers Plugin and select Settings. You can set your own configuration or leave it as it is.
10. Now choose the page which display the Ask Question form and another page that will list all questions.