hi

I want to have website like wikihow.com . can i create it with k2 and its extentions?
which extension of k2 may help me to have that features?
include : posting article by our member , style of showing article in home page , style of add post in each content , style of showing cotent and etc

It can be done with K2.

The modules have to be made with the K2 Content module.
The K2 Users module will also come in handy.

To be honest you should download it setup a demo site and evaluate it yourself.

thanks for your helpful comment.
I like the k2 features but i want some exact some wikihow feature too

how can i have this feature in k2 ? do you have any recommend ?

for example can i make something like comment plugin for k2 that our member can add some step or part for one article with picture and video like wikihow style ?

You can do this with extrafields.
You can set a predefined number of steps and render these extrafields in the front-end.

we can't set predefined for each article .
can we change the comment plugin or we must made a new add on for k2 ?

Yes you can.
You can set a maximum amount of steps and create these extrafields.

You can use FB Comments, Disquss or pretty much every commenting plugin which supports K2.

First of all Wikihow uses Mediawiki. It is hard to compare K2 with Mediawiki set-up since they both are created with different goals in mind. There are similarities with content creations, but there are also a lot of big differences between them. I am currently using Mediawiki myself and changing over to Joomla (possibly K2 or easyblog). Mediawiki is not meant for CMS. It is purely developed keeping in mind for "mass-collaboration". There are many features that MediaWiki provides that cannot be gotten from k2 or even wordpress. You have to try each and evaluate what is best for you and figure out what purpose you want to achieve in your site with your users.

Having used MediaWiki, I can tell you this - It is not easy to set-up and maintain MediaWiki. It requires a level of knowledge and you need to spend time learning it. It wont be a piece of cake like installing Joomla or Wordpress where you can set-up and start using just in a few minutes and with so many options of templates, modules, extension etc... MediaWiki is not like that and it requires atleast intermediate skills just to get started.

Good luck!