Yes, it is. But it still uses an open protocol – so you can switch from IRCCloud to, say, Quassel[1] easily without having to recreate channels or permissions.
[1] Quassel is an IRC bouncer/client combination which handles things like backlog archiving and so on properly – you can connect with multiple clients at once, just scroll up to load more backlog, use web clients, windows/mac/linux/Android/iOS clients, etc.
(The backlog lives in an SQL database, so tools like Quassel-Suche can easily query it, and you can easily export it. I personally stopped using bookmarks, and just search for links through Quassel-Suche instead)
[1] Quassel is an IRC bouncer/client combination which handles things like backlog archiving and so on properly – you can connect with multiple clients at once, just scroll up to load more backlog, use web clients, windows/mac/linux/Android/iOS clients, etc.
(The backlog lives in an SQL database, so tools like Quassel-Suche can easily query it, and you can easily export it. I personally stopped using bookmarks, and just search for links through Quassel-Suche instead)