Sounds interesting, though you might want to check out their privacy policies. +Paribus
can use All information it gathers about you. So all your emails and whatever other forms of input they can get from you. They use this information for their service but also to sell you. They have provisos for ads, etc... You are the product without knowing it. The 25% they take is the least beneficial thing they get from you.
And remember this company gets access to All your emails.
I didn't see a peep in their "privacy" policy about protecting end users. Just how they are going to use the data they collect on you to make a lot of money.