Posted by effulgentsia on December 21, 2011 at 1:53am
The text_summary() function used for displaying text fields with the "Trimmed" or "Summary or trimmed" formatters (i.e., within teasers) has some shortcomings as discussed in #221257: text_summary() should output valid HTML and Unicode text, and not count markup characters as part of the text length.
This sandbox project contains a module for altering those formatters to use the trimming logic being worked on in that issue. This lets you benefit from that issue's work in Drupal 7 without needing to apply a large core patch, or wait until that work is committed.