Survey Telescope and Rapid Response System (PanSTARRS; @2002SPIE.4836..154K) and the Large Synoptic Survey Telescope (LSST; @2008arXiv0805.2366I), their cadences are not ideal and it still requires a decade of operations to accumulate the light curves. This makes it challenging to expand on this promising new approach to probing quasar physics.

There are, however, quasars[^1] with almost two decades of well-sampled light curves – the quasars lying in the regions surveyed by microlensing projects such as the Optical Gravitational Lensing Experiment[^2] (OGLE; e.g., @2008AcA....58...69U), MACHO (e.g., @2000ApJ...542..281A), and the Microlensing Observations in Astrophysics (MOA; e.g., @2002MNRAS.330..137N). For example, the combined phases of the OGLE survey (OGLE-II to OGLE-IV) span 15 years with up to 1000 epochs in $I$-band and a few dozen in $V$-band for approximately 40 million sources with $I<21$ mag in the Magellanic Clouds, and the light curves continue to be extended by the OGLE-IV survey.

The challenge is identifying the rare quasars in these dense stellar fields. A combination of serendipity (e.g., @1994PASP..106..843S [@2003IAUC.8258....1C]), X-ray (@1997AJ....114.2353C [@2002ApJ...569L..15D; @2003AJ....126..734D]), and crude variability measures () had succeeded in identifying only 55 and 28 quasars in the LMC and SMC, respectively, as of 2010. In [@2009ApJ...701..508K], we showed that the mid-IR selection 