What is an ideal platform or service for collecting ideas & feedback from a large group?

Paperform is my go-to-app for surveys and online forms.

Yep, plus one vote for Paperform!

I've been using Typeform for gathering feedback and ideas from users at Tookapic. It has a free version, but with paid version, you can embed the survey nicely in your website.

Hey Emily, Obviously there's a few options already, but I would wager doopoll would be the leat intrusive and cleanest option to use. Give us a try for free first if you like (up to 50 responses). Available in English, Spanish, French and Welsh too. :)

For Product Hunt we've been using FB Groups for this. Works well because everyone already has Facebook. The posts/threading are easy to follow. And the content that's "most interesting" generally bubbles up to the top of the group.