Washington State will be adopting Common Core officially (with state testing) for the 2014-2015 school year.
Currently 45 states (and the District of Columbia) have adopted Common Core. This count includes states who are not currently using the Common Core, but have a plan in place - like Washington State. States who have not yet adopted Common Core include: Texas, Alaska, Michigan, Virginia, and Nebraska.
What I love about this is that all teachers across the United States will be working from the same standards. This means that if I take the time to align all of my lessons on Teachers pay Teachers teachers all across the country will be easily able to use them in their classrooms.
Do I think that Common Core will make us better teachers or students better learners? Not so much. I believe that a good teacher covers what students need to know to be successful in life and in the next grade. It doesn't matter if they are using Common Core or not.
I do think Common Core will make it easier to compare the educational systems within states. Since we are all supposed to be teaching the same things it will be easier to see who is doing it well and who isn't. Getting data from all over the country will help everyone see what is working and what isn't. This, in theory, should make our educational system better.