Taxonomy single tag

Taxonomy Single Tag improves core's taxonomy autocomplete by allowing commas to be used as part of the taxonomy term. To do this, TST limits autocomplete taxonomy fields to a single term.

Why such a module might be necessary is explained at Taxonomy autocomplete without multiple select:

Is it possible to create a taxonomy-input with autocomplete, but without the possibility to select multiple terms? [With] "Free tagging" it's possible to separate multiple terms with a comma, but I [would] like to select only one term. Autocomplete is necessary because 1000+ terms are too much for a single dropdown...

Related modules:

• Unitag
• Hierarchical Select
• Content Taxonomy

Drupal 7 version

There is now a Drupal 7 port of this module. It takes a somewhat different approach than the D6 version -- Taxonomy Single Tag exposes an "Single tag autocomplete text field" widget. This widget can be set to single- or multiple-entry, allowing unlimited tagging with commas and quotes.

When adding a field of type "Term reference," select the "Single tag autocomplete text field" widget option to force the autocomplete field to accept a single term and allow commas. As with the D6 version, this field can be used to add new taxonomy terms or select from existing terms.