You must do this for Steemit
1.) Go to https://coinbase.com
2.) Login or Signup first
3.) Go to https://coinbase.com/price
4.) Click on the star
Info: If you don't see the stars, it seems that this is a somewhat common problem. At the current time, I'm not aware what the solution could be. But you can try to use different browsers.
Why must you do this for Steemit?
Coinbase is tracking this information. There is a good chance that they will use that information to make a decision when listing their next coin. Everyone placing stars on STEEM could get STEEM listed on Coinbase.
This could be the single most important thing you can do for Steemit
Take action and follow the steps above