Remove Automatic Post-saving
Since one of the recent changes, there is now such a thing as "Saving" Posts (The equivalent of what used to be "following" them)
However, when you support a project, you automatically save it, which can be annoying because to un-save you have to reload the page and hit the unsave button. I think it would be better just to be able to save a post when you want to.
You can just turn off the 'notify me when a post I saved ...' options in your settings. You still save the product idea but you can modify what you are notified on.