Hi Marilynj,
In Office 365, we provide the website usage statistics function. You can append /_layouts/usageDetails.aspx after your public facing website URL to access the web analytics report. For example: https://domain.sharepoint.com/_layouts/usageDetails.aspx.
The web analytics report provide Number of Page Views, Number of Unique Visitors, Number of Referrers, Top Pages, Top Visitors, Top Referrers and Top Browsers. Currently, it only provides the reports within 30 days.
Thanks,
Eric Sun