Adding a free response textfield to select component if no response.

No, not directly within Webform. It is actually possible, though it'd take some crafty form-building to get it to work. You can theme the form using the instructions from THEMING.txt or just put <script> tags inline in the Webform description. Add some JavaScript to show the textfield if "other" option is selected.

<script>
$('input[@value=other]').change(function () { $('#edit-submitted-other').slideToggle(); });
</script>

Note that this is totally nonfunctional code, but it sets you off in the right direction. See http://visualjquery.com to learn some jQuery.

I'm moving this to a feature request, because it's common enough and (in my opinion) a strong point that SurveyMonkey has over Webform. I'd like to get it implemented eventually.

I think this is basically a duplicate of: http://drupal.org/node/254728

And if it's not a duplicate of that one, it definitely is a duplicate of this one #330740: "Other" option in select lists for text entry. Let's followup there regarding select lists specifically. The #254728: Conditional fields issue is a bit more complex as I think it gets into all kinds of conditional logic. This request is a bit simpler.

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