RSS stands for Rich Site Summary but could be explained as a news feed that goes to your email, tablet or smart phone.
News feeds are an easy way to keep up with HMinfo having to constantly visit. When HMinfo is updated, the newsfeed will notify you and give you a link to the new content.
Most current web browsers have feed readers built in. You can also use web-based readers or dedicated software. On the HMinfo website you will see an orange square that is the link to set up the RSS feed for you.