lubuntu was taken into the list of Linux distributions by our friends from distrowatch.com some time ago.
Please check out: http://distrowatch.com/lubuntu
Even though we are still in Alpha stage, it seems many people already downloaded it and tried lubuntu already.
The positions in the popularity charts are:
Last 12 months: position 289
Last 6 months: position 235
Last 3 months: position 152
Last 1 month: position 84