Time-Course of Citations (red)
and Usage (hits, green)
Witten, Edward (1998) String Theory and Noncommutative Geometry Adv. Theor. Math. Phys.  2 : 253
1. Preprint or Postprint appears. 2. It is downloaded (and sometimes read).
3. Eventually citations may follow (for more important papers).
4. This generates more downloads, etc.