I'm a massive fan of Segment - we use it everywhere at my company (Clearbit) and my only regret was not integrating it sooner. For example, some things we do:

* Sync Salesforce to Redshift - then perform queries across it * Sync all incoming lead to Salesforce * Enrich incoming leads with person/company data * Fire webhooks to lambda processing incoming signup events, qualifying them, and then triggering subsequent events