Researchers are constantly trying to find accurate quantitative ways to measure the impact of their publications, the journals in which they are published, and the subsequent citations to their work. It is a noble, but ultimately imperfect, exercise.
One method is the Hirsch number (a.k.a. h-index), proposed by physicist Jorge Hirsch in 2005. Another method, the g-index, was suggested by in Leo Egghe in 2006.
If you want to know your h-index (or g-index, for that matter), you can try QuadSearch.
Here are my results (H-INDEX = 8; G-INDEX = 12 today).
An interesting feature of this site is that you can compare two authors side-by-side: just click on 'Compare', type the second author's name, and have fun!
Thanks to Liam Mayron for pointing it out to me.