Apple Color Emoji
Si Daniels, Lead Program Manager for fonts at Microsoft (via John Gruber):
Of even more significance is the fact that the glyphs included in the font are Unicode encoded. In an effort initiated by Google and with significant help from Apple and Microsoft, 722 Emoji symbols were included in the recently published Unicode 6.0 standard, putting Emoji on par with the Latin alphabet and other writing systems encoded in Unicode. This means messages and documents containing Emoji are fully searchable and indexable, and Unicode Emoji fonts are included with Windows Phone 7.5 and the Windows 8 Developer Preview.
