Larry has Yahoo mail and he gets a ton of spam. He can't really delete all of it at once, because sometimes email from friends gets in there. Leo says that if it's any consolation, everyone gets spam. Yahoo is just doing a poor job of filtering it. Leo says that we've lost the battle against spam, and some webmail providers filter it better than others. Google uses a technique called collaborative filtering, where users let them know if an email has slipped pass their filters and it adds to the list.
Alan needs to use a service like Constant Contact or Mailchimp for his business emails, but he's concerned that people may not read them or that they won't even get through because of spam and malware. Leo says that's the entire idea behind using those services since they know how to format the email with opt-out options, proper settings, etc.that prevent them from being relegated to Spam filters.
George wants to know how good the spam protection is with Gmail. Leo says that Gmail's anti spam filters are great and getting better. George also wants to be able to get his mail from other mailboxes. Leo says that there's a unified mailbox feature he can enable to do that with. Set up with IMAP. That'll give him the least delays. Gmail will also allow him to create filters and tabs to filter and sort his mail.
Richard is concerned that Google will read his email and use his activity for advertising. Leo says that Google only has computers read email, and it does this to filter spam. No human is reading through emails.
The clause that Google will use his activity to advertise means that Google will search his email for keywords, like it does spam filtering, and will customize ads on his page based on that activity. So it's for stuff he could use. It's important to note that nearly every other ISP and service does this as well. And he's getting gmail for free.