Rate rules are techniques to protect your community from spammers and web bots that attack or spam your community by posting the similar message several times in a row. You can build rate rules to alert your community moderators of suspicious spammer-like activities in your community or freeze a member on the spot.
Take for example, when the universal shipping introduces a rate rule to their comunity, Community Moderators will now be alerted when a member post more than one file to the community within a 15-minute window thereby making them frooze the account accordingly.
Confidentiality is a virtue which we need to secure information by limiting computer access to authorized personnel only. People trust us to keep their private matters private. Keeping that confidence is an important aspect of trust.