In InDesign, how do I create a bookmark (i.e., a bookmark that will be exported to a PDF file) that is a hyperlink to a URL?
You can use third party plugins for creating a bookmark in InDesign. BrowsePlus InDesign Plugin is a web browser InDesign which allow you to manage bookmarks,save and edit bookmarks, watch videos, multiple tabs, check email, simply drag & drop images within InDesign. http://metadesignsolutions.com/products/browseplus.php
You include the Bookmark by going to File>Export and choose PDF(Interactive) and Choose the interactive options.
Or you can choose File>Export PDF (Print) and change to Acrobat 5 compatibility, the Bookmark and Hyperlink is now available to tick.
You create bookmarks by using the Window>Interactive>Bookmarks or you can make a Hyperlink by going to Window>Interactive>Hyperlinks.
Note that most urls written with www. or http or https etc. will automatically be linked in Acrobat.
This isn't the easiest thing to find in InDesign. The whole issue of interactive elements and hyperlinks has been in a state of flux through the last couple of versions. The instructions that follow are for CS5 or 5.5, and should hold good for CS4:
Open the Hyperlinks panel: Window > Automation > Hyperlinks
Highlight the text you wish to make your bookmark.
From the panel flyout menu select either "New Hyperlink" if your text is not a URL, or "New Hyperlink from URL" if your text is the URL. (Note: Do not choose "New Hyperlink Destination", which places a named anchor to which an internal hyperlink can refer.)
If you have a number of URLs scattered throughout the document, the flyout menu option "Convert URLs to Hyperlinks" will do them all in one swoop.