That is half a million! The size of the database where you test will be a major factor in how many DNA matches you get.
23andMe is an autosomal DNA test, which means you will receive matches on your maternal and paternal side. You will also get your maternal haplogroup regardless of your sex and your paternal haplogroup as well if you are male.
I am a huge 23andMe fan. I have just received my 15th, 16th and 17th kit to test family members. Before you tell me I need to be the founding member of Genetic Genealogists Anonymous, I have to tell you that there are people out there who have tested even more family members. It can be a very addictive hobby! I have found lots new cousins (with DNA and paper trail matches) on 23andMe.
Half a million is a lot of people, but 1 million would be even better than half a million, so check out 23andMe and Explore your DNA and join over 500,000 genotyped members.