I have encountered a very odd problem. I have two hyperlinks in my InDesign (v8.x) document. One is an email link, the other a twitter HTTPS link.
The email link works (I suspect this is even automatic... see next problem) but the Twitter link (text uses the format @twitter_name). If I open Window > Interactive > Hyperlinks panel, both links are correct and work. However, when I export to a PDF, the email link works but the Twitter link is interpreted as an email link (mailto:).
I experimented by removing the '@' symbol from the text name, exported to PDF... and found that it was no longer a hyperlink of any kind. What is going on? This shouldn't be so complicated.
BTW, I even tried making a new text hyperlink for the Twitter account - same results.
Hmmm.... I cannot remove my own posting?
Oh well, perhaps someone else will find this useful, some day.
It turns out that the problem was caused by not selecting, General > Include > Hyperlinks at the point of Exporting to PDF. So simple... foolish me.