This is the actual problem at the heart of it all. And even if it were more profitable to take subscription fees than to serve ads, what's stopping you from "double dipping" and serving ads anyway?
ArsTechnica (obviously a very different site compared to SO) has an ad free subscription model where it also removed all trackers for paying subscribers. It's possible to do this in an ethical way. Whether the site publisher is interested or not is a different matter.
You think the NY Times, Linkedin, etc. is going to have the same response as StackOverflow? Good luck even getting in touch with someone who knows what you're talking about.
If LinkedIn (to choose a random example) advertises one of the perks of subscribing is that you won't be tracked, and then tracks you anyway, that's a story for The New York Times et al.
Sure. But my point was that the NYT is an example of a paid service that openly serves you a big pile of invasive ads, even if you're a paying subscriber.
Imagine if all the ads in the print edition were spying on and tracking your every move.
Very likely. I'd pay hundreds of dollars a year to Gogle if they guaranteed* me, with severe legal repercussions otherwise, that they wouldn't track me, or allow a single bit of my data, anonymized or not, leave their servers, or be used in any other way that wasn't for my own purpose.
Re-selling digital personas as commodities must be far more lucrative.
I actually wonder about this. SO's typical user is tech-savvy, and I would imagine many access the site with adblockers on (I do). So I suspect my value to the site in terms of ads is close to zero. I would happily pay a monthly subscription to know that the service will remain, given how much value I derive from it, if that gave me the assurance that they won't track me with ads/cookies/fingerprinting.
Their other income is from job ads, and I guess the value is that they have lots of data points about their logged in users (with scores high enough to imply they've interacted with the site a fair bit), in the form of what is posted, worth more than the aggregated list of websites that a user sees (as reported by ads).
I'd love to know more about this, as I have very little understanding of the economics of serving targeted ads. How much can they be making from ads?