Looks The Same, Works The Same
Attachment file size limitations are the same as your account's limitation. So for free Yahoo! Mail users, the limit is still 10MB. Enclosing pictures can be set to appear within the email instead of being attached as a separate file. Although upon receiving an email sent to myself with an inline image attachment, I was not able to view it, but I was still able to download the attachment as a JPG file. On the other hand, rich, HTML emails are displayed properly in Zimbra.
You can also use the search function available in Yahoo!'s web mail right in Zimbra Desktop, where users can type in a string of text to find emails that you want to bring up.
What's most important to know is: everything you do in Zimbra Desktop will be reflected in Yahoo! Mail, and vice versa. Whatever actions performed in Zimbra Desktop's Mail will be reflected in Yahoo!'s web mail counterpart, and the other way around. The Inbox is automatically sychronized and you can also choose not to sync certain folders. This is very useful if you have a lot of emails archived in one folder (which will take a long time to sync). This feature is extra handy specifically for Yahoo!'s dedicated Spam folder so you don't have to download unnecessary emails.
Your mail preferences on the web carries over in Zimbra Desktop. For specific configurations for the desktop client, a number of options can be set by users to control how Zimbra Desktop behaves in the Options tab.
It's also comforting to know that your Yahoo! contacts are retrieved from your account's online address book. So if you loved your contacts auto-filled when you're typing for recipients when you're composing a message in your web mail, you can still enjoy this feature in Zimbra Desktop.