This is to let you know that your hub still needs a summary written.
In edit mode, go to the right side of your page, where the reorder, tags, SUMMARY, etc. are listed. Click on the summary button and an empty white box will pop open. This is where you add a short (2 or 3 sentence) summary of what your hub is about. It helps your hub get found and read by searches. This is a new addition to the edit mode (the "A" by your hub listings). Have fun with it, it is simply another way to market your work! Good luck!