Microsoft has finally added Emoji (2, at least) to the Segoe UI symbol font in an update to Windows 7.
Microsoft KB2729094 titled “An update for the Segoe UI symbol font in Windows 7 and in Windows Server 2008 R2 is available” is presumed to be made available through Windows Update soon.
This article introduces an update to the Segoe UI symbol font in Windows 7 and in Windows Server 2008 R2. This update adds support for emoji characters and some control glyphs that are included in Windows 8 and in Windows Server 2012. Note Emoji characters come from emoji-capable platforms and devices. The platforms or devices enable users to easily insert emoji characters into documents, email messages, or chat conversations by using an emoji picker feature or an emoji palette feature. In Windows 8 or in Windows Server 2012, these characters are inserted by using the on-screen keyboard.
Microsoft backports Windows 8 emoji for Segoe UI Symbol to Windows 7