[cstejerean]

From the point of view of simulating actual users, the fact that some random third-party resource on the page failed to load is not particularly relevant. That happens all the time as I browse around the web, and I never have to care about it as long as the site continues to function. So it very much is an edge case compared to the page itself failing to load.

[nirvdrum]

A JavaScript file failing to load will bork most pages. A CSS file failing to load or a key image will cause most people to quit. And an Ajax request failing in a single-page app will render it useless.

But, my point of view is from actual Selenium users. This is framed by providing support on the IRC channel, on the mailing lists, triaging the issue tracker, and by interacting with people at SeleniumConf and the local Boston meetup. It's not some fringe use case and I'm not arguing the point for the sake of arguing it. The original supposition that it's an edge case is not accurate. And sure, the web breaks. That's why people using Selenium would like a way to catch that. And that's a big part of why the BrowserMob Proxy project exists.

[encoderer]

"A JavaScript file failing to load will bork most pages. A CSS file failing to load or a key image will cause most people to quit."

Wha?

Sure, if, say, "app.js" fails to load, you have a problem.

But an analytics script?

A 3rd party ad script (which is what the GP gave as an example)?

These things can and do fail all the time.