Here's Google's support article describing what "gccTLDs" are: https://support.google.com/webmasters/answer/1347922
The Isle of Man has about 84,497 inhabitants -- not that much. In contrast to this, there are tons of websites that use the .im TLD for other purposes, mainly messenger applications:
* ejabberd.im = XMPP server * trillian.im = multi-platform messenger * imo.im = mobile messenger * whistle.im = secure mobile messenger * plus.im = mobile messenger * pidgin.im = XMPP messenger * disa.im = mobile messenger * peer.im = group chats * prosody.im = XMPP server * adium.im = messenger for Mac * tox.im = secure messenger * doit.im = to-do list / time and task management * tweet.im = frontend for Twitter / messenger applications * hosted.im = business communication * blah.im = XMPP server * coccinella.im = XMPP messenger * oneteam.im = business communication * delete.im = ephemeral messaging * thenews.im = frontend for Hacker News / Designer News
Other TLDs (all of them belonging to larger countries) have already been made a gccTLD:
* .cd = Democratic Republic of the Congo = 77,433,744 inhabitants * .co = Colombia = 47,425,437 inhabitants * .la = Laos = 6,695,166 inhabitants * .dj = Djibouti = 810,179 inhabitants * .me = Montenegro = 625,266 inhabitants * .sr = Suriname = 566,846 inhabitants * .bz = Belize = 334,297 inhabitants * .ws = (Western) Samoa = 194,320 inhabitants * .fm = Federated States of Micronesia = 106,104 inhabitants * .sc = Seychelles = 90,024 inhabitants