librato.comは安全ですか？

According to CruchBase, Librato does "Real time operations analytics for metrics from any source." So basically they perform system monitoring. They were acquired by SolarWinds in January 2015, and SolarWinds is all about performance monitoring of systems, which helps in troubleshooting and capacity planning. As such, this company would have little interest in tracking individuals. It doesn't look like they even gather the metrics for the most part. They analyze metrics taken from a number of tools instead. They probably do look at session data to see what visitors are viewing and how they go through the system to determine if there are ways to improve responsiveness/performance. They goal here is not to sell products.