You also gain access to more information about your ethnicity and the opportunity to connect with potential cousins. Here are two early observations I made in signing up:
1) You'll be asked to fill out surveys about your family's health. Totally understandable since the main goal is medical research. Then there's an option to connect to your social networks to analyze "social preferences" --- thanks, but I'll pass on that one!
2) They're very open about what they will and won't do with the data you share. The researchers go so far as to link to their own personal genome to prove they have "skin in the game" too. Reminds me of the CEO of that one identity theft company that gives out his social security number in the commercials. What happened to that guy anyway?
The nerd in me can't resist DNA.LAND. So, I'll report back soon as to how it's going and hope you'll share your experience in the comments as well.