Yahoo! Mail beta now provide chat with your Facebook friends in Yahoo! Mail! On the left, you'll see "Facebook Friends" under "Online Contacts". If you click on the thunderbolt, you'll be prompted to authenticate on Facebook Connect. Once you've authenticated, your online Facebook friends will appear below "Online Contacts" and you can chat freely. As if Facebook was not addictive enough on its own, right?.
Giving you more message space. Now you can scroll the entire Yahoo! Mail page so you can see as much message content as possible. Just go to Options>Mail Options and select "Scroll content of the entire page".
Also, a paginated Inbox list view, lets you view 50 messages in your list and click to go to the next, previous, first or last pages. When you click on a message subject line, the message loads in a full tab. You can change the number of messages per page by clicking on Options>Mail Options and then selecting from 50, 100 or 200 messages at a time. If you still prefer the preview pane mode, you can also change this setting by going to Options>Mail Options and selecting "Scroll each panel on the page individually".
Yahoo! Mail also now give access to past IMs in Yahoo! Mail Beta. Just click on "Conversations" on the left side just below "Inbox" and see all your past IM conversations from Yahoo! Mail Beta (and the latest downloadable Messenger client).