I understand that technically there can be 18446744073709551615 users (db limitations). But I heard at a talk that the vanilla install of WP in actuality can't handle many users that well due to caching issues, especially if you add user_meta. Can someone confirm this?
The speaker recommended that to make wordpress more able to handle the large amounts of users it's a good idea to install BuddyPress, but honestly the code is a mess and there is little documentation. So I'm considering scrapping that and going vanilla again.
Does anyone have any expertise and can shed light on this?