New in this release:
The text library provides an efficient packed, immutable Unicode text type (both strict and lazy), with a powerful loop fusion optimization framework.

The 'Text' type represents Unicode character strings, in a time and space-efficient manner. This package provides text processing capabilities that are optimized for performance critical use, both in terms of large data quantities and high speed.

The text package provides character-encoding, type-safe case conversion via whole-string case conversion functions. It also provides a range of functions for converting Text values to and from ByteStrings, using several standard encodings (see the text-icu package for a much larger variety of encoding functions). Efficient locale-sensitive support for text I/O is also supported.

http://www.serpentine.com/blog/2010/09/01/major-version-of-the-haskell-text-library-0-8-0-0/