Lockin could mean they use the service, or stronger, they use the service on the official UI (which may have ads). I think for Slack, the first type of lockin i

Lockin could mean they use the service, or stronger, they use the service on the official UI (which may have ads). I think for Slack, the first type of lockin is enough (a paying user is a paying user, whether they use IRC or slack.com), whereas for FB the second type of lockin is better because only that can be monetized.