Thred Monetisation

As at 4th June 2015 these apps are included in the top 100 downloaded "Free" apps in the US. These are in order top to bottom as most downloaded.

I have omitted anything irrelevant to possible association with Thred.

FB Messenger
Facebook
YouTube
Instagram
Snapchat
What's app Messenger
Kik Messenger
Twitter
Pinterest
Skype for iPhone
Vine
Google Photos
LinkedIn
Tumblr

Quite a list there..

Now let's discuss monetisation.
If Thred is launched as a "Free" app I doubt we will see problems hitting download milestones but how will Thred make money?

Through advertising?
Through partnership agreements?
What are people's thoughts or knowledge on this subject?

Do you think Thred will or should charge a download fee or should it be "Free" to encourage users given it's potential partners apps are "Free"?

It's games that charge more often than not as a general rule of thumb as games make up the majority of the top "Paid" apps downloaded..

Fair question?
Anyone?