I've confessed a few things I've never told anyone before. The experience of being forgiven was very meaningful for me.
However, in addition to the sacrament itself, I got a kind of comfort from "someone else knowing." Obviously, God knows my sins, but for another human to know these particular sins was a huge relief - something off my chest, feeling less alone, less like I was hiding. At my confession, I talked about the weight that I had been carrying around for years, and my priest gave me good advice.
I would never bring it up, but I often wonder if my priest remembers what I confessed.
I know that priests cannot reveal anything they hear in the confessional, but do they generally remember?