These are two new features on Gmail that are kind of cool. Have you ever started to type out an email to someone, let's say their name is Bob, and you just let the autocomplete do the work and you end up sending it to the wrong Bob? Gmail can now help out with that. If it senses that that particular Bob is not normally associated with the other people on that list, it will ask if you really mean that Bob. It will also suggest you add Bob (the right Bob) to a list that he's normally found on. Well, now you know what all those Google employees have been spending their time on. BOB CLARIFICATION.
You can also create your own customized Gmail background because that worked so well for MySpace.