As long as you don't buy stuff based on ads, and unless the product benefits from network effects, you are just making ad-supported products less profitable by using them, and hence contributing to their demise - either the ads are pay-per-click, and then you are just raising its costs without providing returns, or they're pay-per-view and then you're making the ads less valuable for advertisers (and hence less profitable for the service).

It's the people clicking on the ads that are keeping them alive.