@sazius I think you're right, user-facing programs can easily interrupt flow. Firefox doesn't need to (because search revenue) but they do in subtle ways occasionally. More programs could, and get away with it, particularly if they had strong relationship with their communities already. Are there any good examples? 

Don't tons of 'apps' do in-app upselling to a proprietary version or other in-app purchase? Do any faif apps ask for donations or offer in-app purchase of crowdfunding-like perks? I guess I should try more 'apps' so that my knowledge isn't secondhand.

I know the bigger problem is not having millions of users, but lack of $ for development and marketing only perpetuates that problem.

As @wolftune might be reading, perhaps after snowdrift.coop finally launches with real money, it should somehow enable in-app/program pledging.

I don't know that there's a solution for Conservancy wrt applications interrupting users, other than some of its member projects raising lots of money that way and giving Conservancy its cut. But I suppose (modulo it not having enough resources to do anything beyond what it is already doing, etc) that it could conceivably also help member projects do in-application asks.