Tag & vocabulary module or technique that mimics stack exchange tag behavior? I am looking to recreate the tagging functionality of stack exchange:
- enter tags on a single text input line, with comma separation.
- add new tags to the taxonomy
- increment count of existing tags
- inline suggestion based on initial character entry

Is there a Drupal module or set of tools that provides this functionality?
The Autocomplete Deluxe module is perfect for this. It adds an enhanced autocomplete element, that uses the JQuery UI autocomplete. Although it will not provide the term count, the behaviour is similar to stack exchange in every other way.