  We discuss issues concerning the physical nature of intervening MgII quasar
absorption systems in light of results from our recent surveys using SDSS EDR
QSO spectra and data obtained at the MMT. These surveys indicate an excess of
weak $W_0^{\lambda2796} \lesssim 0.3$\AA) systems relative to the exponential
dN/dW distribution of stronger systems. The incidence of intermediate-strength
lines shows remarkably little evolution with redshift, thereby constraining
models for the nature of the clouds comprising these absorbers. The total
distribution does evolve, with the incidence decreasing with decreasing
redshift in a $W_0^{\lambda2796}$-dependent rate (the strongest systems evolve
the fastest). This suggests that multiple populations that evolve at different
rates contribute to the incidence in a $W_0^{\lambda2796}$-dependent manner. We
also present two images of fields containing unprecedented ``ultra-strong''
($W_0^{\lambda2796} \ge 4.0$\AA) MgII absorbers.
