Inside OS X 10.8 Mountain Lion GM: Mail 6.0 & Notes
Inline find and improved message navigation
Also new in Mail 6.0 is Safari-style inline find for words within an email message. Previously, you could bring up a standard Find/Replace dialog box (below) and iterate through a message looking for a specific term.
Now, there's a search field at the top of messages that highlights every occurrence of a particular phrase in the entire message, together with a standard counter and selection controls (below).
Another handy feature that feels borrowed from iOS is the ability to zip to the top of your long list of inbox messages simply by clicking on the sort bar; no need to manually scroll upward through potentially thousands of messages. Once you skip to the top of your messages, you can still perform a new message sort by date (default) or by attachment, flags, from, size, subject, to or unread status, either in ascending or descending order, just as you can now. This shortcut just makes navigating through your search results (or between results) faster and easier.
Sharing Sheet, iCloud features
Two additional features of Mail 6.0 reflect the trend of Mountain Lion's general direction toward social connections and iCloud connectivity. When you share a web page from Safari as an email message, Mail 6.0 allows you to select how you'd like to share the page. Your options are as a full web page with graphics (below top), as a streamlined Reader view with just the main article's text, or an attached PDF file and URL (below middle) or URL only, selectable within the Mail message window from a popup (below bottom).
Another big Mountain Lion feature having an impact on Mail is iCloud. Previously, Apple offered to sync Mail account settings (including mailboxes and rules) via iSync to MobileMe. That functionality was retired with MobileMe, leaving what some feared would be a big feature hole (along with other important synced data such as Keychains and other, third party application preferences).
In Mail 6.0, Apple automatically sends mailbox, rules and mail account settings to iCloud, so when you configure a new system, all your settings can be synced up from the cloud. Additionally, Apple is now also pushing new updates to iCloud, including your recent senders, favorites, email signatures and smart mailboxes. Expect other apps to follow suit, making use of iCloud to do things that formerly relied upon Sync Services.
Apple's new "Mail, Contacts and Calendar" pane in System Preferences makes it easy to set up new email accounts, along with support for new account specifically targeting service providers in Greater China, where Apple is seeing so much new growth. Interestingly, while Facebook support isn't finished yet, there's not yet any mention of adding Facebook messages or IM to either Mail or Messages, although is is very likely to change before Facebook support ships for Macs running Mountain Lion.
On page 3 of 3: Freestanding new Notes app