Hi Sander, it should work, though we haven’t tested Iframely with BB press specifically.
BB Press relies on oEmbed features of WordPress – which Iframely extends.
You need to enable embeds for your BBpress first, it seems:
https://codex.bbpress.org/features/auto-embed-links/
I have tested it and it does work when I insert the shortcode with link manually.
Typing the link and pressing enter in the topic reply box does nothing.
I would be very interested in a solution where you would press a WYSIWYG icon in the editor and then a popup would appear, enter a URL and then the plugin would place the URL in the shortcode by itself.
Example for BBpress: https://www.dropbox.com/s/eukhdohy26lh8ul/embed.jpg?dl=0
