| Customizing Message Text | Using Emoticons | Using Audibles | Using Buzz |
You can change how your text appears in your instant message conversations in both your IM window and in the IM windows of your contacts (for those contacts who allow your changes to display in their IM windows).
Yahoo! Messenger provides two ways to customize conversation text:
You can also control how your IM window behaves when a contact sends you an instant message using fonts and colors that differ from your choices.
(More Details)
To customize the text in all conversations:
Open the Messenger Preferences window by selecting Preferences from the Messenger menu in your Messenger window or from the Conversation menu in your IM window.
On the left side of the window, select the Appearance category.

On the right side of the window, click the Change Fonts & Colors button.

The Message Text Style window opens.
Change the style settings you prefer, and then click the OK button.

All conversations that occur after you click OK use the new style settings, unless you change the text in a specific conversation.
Tip: These text changes don’t affect IM windows that were open before you made the changes.
To customize the text in a specific conversation:
In your IM window, click the text formatting button to display the formatting tools.

The formatting tools appear below the conversation area.
Use the formatting tools to make desired text style changes.

These text style changes affect this window only. The text in any other open IM windows remain unchanged.
Tip: Similar to a text editor, font changes made in your IM window apply to text entered after the change. To change existing text that has not been sent, select it, and then apply the new formats.
To control how your IM window behaves when other users change their fonts and colors:
Open the Preferences window, as shown above, and select the Appearance category.
In the section titled When other people customize their fonts and colors, check Always use my fonts and colors to use your font and color settings for all sent and received messages, regardless of what other users have specified.

Tip: To allow your IM window to display a contact’s font and color choice in their messages, follow step 2, but uncheck Always use my fonts and colors. The messages you send continue to use your font and color choices, and the messages you receive use the contact’s font and color choices.
Changing the font and color of your instant messages is one way to express yourself in IM conversations. You can also express a mood by adding emoticons to your instant messages.