With multi-logs, the multi-domains logs on a shared hosting can be separated from the main domain logs, making it an ideal tool for resellers.
When you add a multi-domain on your hosting system, you can choose to separate the multi-domain logs by ticking the "Separate logs from the main domain" box.
You can then access the logs for this domain on a different page to your main domain logs.
You can also authorise people to access to these logs. So if you host several websites on a shared hosting system, you can provide each website owner with direct access to the statistics for their site.
The multi-log is the first step toward shared services. OVH wants to provide this for resellers and customers that manage multiple websites on one shared hosting system.
A free option.