Most of the videos and articles I share go to my Facebook wall, how can I post them on news feed
All videos and articles you share go to your Facebook wall and your News feed not necessarily your friends' News Feed.
When you post content, a story will be published on your Wall and may be published in your friends’ News Feeds (assuming your friends have not hidden your stories). Any action that you take will abide by the privacy settings you currently have set for News Feed and Wall. You can adjust these settings at any time by visiting the News Feed and Wall section of your Privacy Settings page.
how can I post them on news feed
Using the publisher feature , the box at the top saying What's on your mind? should handle this. Also using third parties that you give publishing permission can accomplish this as well.
Everything you post is subject to the privacy restrictions you set at the time of creation. For example, if you create a photo album and restrict it from certain friends, those friends will never see that photo album in their News Feed.
If your update hasn't appeared in News Feed after several hours (when the setting is placed on Most Recent), please submit a report here.
[Source Facebook Help ]
Your "news feed" is what Facebook determines are the most relevant posts that other people post (and yourself sometimes). You can't control what goes in there directly, besides blocking certain people.
Facebook determines what shows up in your news feed by monitoring the people who's pages you visit, post on, comment on, etc. Basically if you ignore a person you will see their posts slowly disappear from your feed... Unless they have a post that a ton of people you do follow more actively comment on.
I'm sure there is even more logic that goes into it than that, but to summarize, you can't "post" to your news feed, it's just a collection of things facebook thinks you are interested in.