Back when companies had offices, there was a button on the phone labeled "all call". It allowed you to page every speaker in the entire building at once.
"Tom P., you have a package at the front desk!"
It was a lot easier to hit all call than to just track down Tom. After a while, this group interruption gets tiresome because it's so wasteful. You interrupt 100 people to reach one, or you get ten offers of help (or someone to buy your hockey tickets) when one was all you needed.
Now, of course, the entire world hears your all call.
"I'm looking for this tool. Anyone know where to find it?" 300,000 people see it, 230 tell you the answer, but of course 229 of those contributions are wasted.
Marketers love the all call, as long as it's cheap to interrupt everyone. And we waste all that attention, every single day. As long the game theory rewards the waster, the one who corrupts the system and hurts everyone else, it'll continue.
[aside: This leads to spam filters and inefficiency and we all suffer. If you've been waiting to hear from me because you filled out the form about road trip or the nano MBA, please check your spam filters! I've already written back to everyone via the mailchimp email service, but they report only a 50% open rate on those notes (which is way higher than industry average, amazingly). So, please check and thanks for your patience.]