Yahoo! has rolled out a new homepage that allows you to get updates from social networking sites like Flickr, Facebook, Yahoo! Profiles and more. It even allows you to view Gmail on Yahoo! front page.
Read this article to get more information about the homepage – Yahoo! Corp Blog
This post is mainly for people who are having problems connecting facebook and Yahoo!
If you have already added facebook on the Yahoo! homepage and are unable to view facebook, follow the instructions mentioned below. The screen which comes again and again should look somewhat like this.

Step 1
Login to facebook and mouse over on the Settings tab. Click on Application Settings

Step 2
Select the Authorized option from the dropdown from that page.

Step 3
Remove the Yahoo! application from the list(Click on the x). It should be somewhere at the bottom of the page, watch out for a purple Y! logo. A confirmation screen will appear, select Remove.

Step 4
Now open the new Yahoo! home page and click on Edit.

Step 5
Search for facebook application and remove it(click on the small x), click the I’m Done button.

Step 6
Now click on the Add option, search for the facebook application and add it.

At this time, we have successfully removed the facebook application from Yahoo! homepage & revoked the permissions on Facebook. Now we just have to mouse over on the facebook app & follow the instructions. Everything should work fine.
I’m listing down the steps to make things easier for you’ll.
Step 7
Mouse over on the facebook application on the Yahoo! home page, this is how your screen should look. Click on login to facebook.

Step 8
Click on Connect

Step 9
Select Allow Access

Step 10
Select the Continue option for "Allow Yahoo! to access my News Feed and Wall"

Step 11
Select the Allow Publishing option on the next screen

Step 12 (Last step)
Select the Allow Offline Access option. After selecting the allow offline access option, the page will refresh and you will be taken to the Yahoo! home page.

Mouse over on the facebook tab and enjoy!
This is a quick fix for the problem, YMMV. Leave a comment if this worked for you or you faced any other problem. I’ll see if I can help you.
[Update] Yahoo! is working with Facebok to get this resolved as soon as possible
Comment from Yahoo! product team:
"Hi, I’m Andy from the Yahoo! product team. I’m sorry that it’s still not working for all users but please know that we are working hard with Facebook to get this resolved as soon as possible. Thank you for your patience and feedback. We’ll keep you updated."
