Would you miss it if it weren't there?
Vogue magazine regularly runs more than 600 pages in length. And that's fine, because it's worth more with the ads than without them.
On the other hand, if the ads disappeared from Twitter, would the service be better or worse?
Media companies of the future will be built on ads we want to see, ads we'd miss if they were gone.
[And yes, I mean your fundraising newsletter and your Facebook updates, and I mean the announcements on the speaker at the airport and the robocalls too.]