Ask HN: Do you use Gmail and have an issue with unsolicited mail?

I have an no idea that I'm thinking of building out but need to get some feedback. Simple question really:

Do you use Gmail and have a problem with unsolicited email getting into your inbox (and not being classified as spam)? If so, how do you deal with it?

Would a simple service that can easily block domains, as well has having public lists of domains that send unsolicited email that you could subscribe to be of interest to you?

Thanks!