As far as I remember, Senior Member is awarded based on post count, but we will remove the rank title if we feel that you have talked out of your arse to get there.
Either way, you are better off not adding your own rank to your profile. The admins have given or allowed ranks to a select group. This group is easily monitored using the forum admin controls. Any new or unintended members are likely to have their ranks removed.
The greatest delight is to mark one's enemy, prepare everything, avenge oneself thoroughly, and then go to sleep.