  We present a spectroscopic analysis of nearly 8000 late-type dwarfs in the
Sloan Digital Sky Survey. Using the Halpha emission line as an activity
indicator, we investigate the fraction of active stars as a function of
spectral type and find a peak near type M8, confirming previous results. In
contrast to past findings, we find that not all M7-M8 stars are active. We show
that this may be a selection effect of the distance distributions of previous
samples, as the active stars appear to be concentrated near the Galactic Plane.
We also examine the activity strength (ratio of the luminosity emitted in
Halpha to the bolometric luminosity) for each star, and find that the mean
activity strength is constant over the range M0-M5 and declines at later types.
The decline begins at a slightly earlier spectral type than previously found.
We explore the effect that activity has on the broadband photometric colors and
find no significant differences between active and inactive stars. We also
carry out a search for subdwarfs using spectroscopic metallicity indicators,
and find 60 subdwarf candidates. Several of these candidates are near the
extreme subdwarf boundary. The spectroscopic subdwarf candidates are redder by
\~0.2 magnitudes in g-r compared to disk dwarfs at the same r-i color.
