Also note that the activity bar is based on consistant activity over the past month, with activity in the most recent week being more important than activity 3 weeks ago. You cannot build your activity in a day by posting a million posts. You have to keep up a record of everyday activity to make it go up, and remember that 100% activity reflects visiting and making posts every day for the past month. If you slip, it'll be 30 days before you can regain 100%, so don't complain that it's not rising.