You can create a campaign sub break down of MURL/vanity url traffic based on any naming methodology you like. Use SAINT to upload and modify it.
The ID in this case external ID type now can allow you to pass evar data of users journeys after hitting the destination URL(via the vanity) this eliminates issues where server redirects mess up tracking. This is great to show campaign impact on traffic and even subsequent events users fire. Great in creating campaign segments.