Seniority is measured differently in each company, and most frequently, it only takes into account how many years you have been working as a programmer, instead of how hard or easy it is what you do every day. I have seen seniors copy and paste code, or even worse, write their own spaghetti code; and juniors solve the most complicated problems noone else could.
Do I know of a better way to measure skills? Heck yeah, see Programmer Competency Matrix: http://tiny.cc/7q24iw
It's all about passion.