And companies started dropping that when it became very important to their business model that they maximize the amount of data they can collect about a user. 3rd party clients for my service? Unacceptable, can't spy on the user as much there, and can't advertise at them. Communicating with users on other services? Unacceptable, I need those users on my service so I can spy on them too, and besides those other services won't talk to mine for the same reasons.
Don't know why you're being downvoted when this is exactly the case in my experience. They never said "spying" outright but it's definitely why walled gardens like AOL popped up like wildfire in the 90s and why stuff like AIM was the exception and not the rule.
AOL was not about spying on you, it was about collecting that sweet monthly fee.
And anyone who lauds Apple for bringing tech to the masses should consider that AOL did the exact same thing for the Internet and really brought a glimpse of the Internet (not just the web!) to the people. Yes, real techies might want to install their IRC client of choice and fine tune settings and all that, but Grandma just wanted to click on Chat from her home screen, go to the "Recipes Room" and talk about cookies.
It was the same "less choice/more consistency" of technology that let Apple get so big, with the same huge mass appeal (but with less panache).
AOL was more 'spatial' vs. the netnerds obsession with everything has to be (ASCII)-text delivered by simple but sometimes obscure to the average user, means.
I sometimes think one could easily replicate large parts of that with
