Correct me if I am wrong @jpphotography and @for91days, but I think they do not collect any taxes right now. Their main goal is to improve the app and add some new features. I don't know how it will be in the future. Personally, I think that taxes are not a bad thing at all. (As @onealfa would say, there is no free dinner and free cheese is only for the second mouse).
The most important thing is the quality of the platform, quality of the posts (they do manual curation) and a good community. Reaching these goals takes a lot of time and effort and at the end of the day, people doing it should get somehow rewarded and the project should not be funded from their own pockets as it might not be sustainable. Actually, I really like @threespeak business model. They collect a small monthly fee. This scares spammers away. @travelfeed do it in another way. They encourage writers to write at least 250-word articles or longer.