Gmail will now let you import email and contacts from other email providers like Yahoo, Hotmail, and AOL (and a bunch more. Full list at the bottom of the article). This means that if you have an old account that you’d like to merge into your Gmail account, you can do so.
It also means (and this is what Google is pushing for) that users of other services can easily start new Gmail accounts without abandoning everything they have built up with another provider. Google is making the switch more enticing.