I’m sorry, but if Facebook really wants to “improve the user experience” then they’ll go the full nine yards and give those users a handy, easy to use “Delete” button they can use to erase their profile from the social network.
The ability to opt-out is one of those basic user rights I believe need to be part of any and all sites, platforms and services. That’s simply good customer service. There’s nothing to be gained by keeping a user penned in, not letting them leave and only honking them off. The only thing that results from that sort of policy is a useless number that, unfortunately, advertisers and analysts will be all too eager to buy into.
The number of active users in any given period is always more interesting and accurate than a generic “membership” number. Heck, I’m a member of Facebook but haven’t done much of anything with my profile in about two weeks. So I’m essentially useless if an advertiser has bought an ad based on membership numbers in that time.
Much better to let people leave when they want. Or at least make “deactivation” of an account mean something, with friend requests and other communications from the site actually ceasing. All of that, even the time someone opts to take off from actively participating on the site, is part of the user experience and policies need to be in place to optimize that.