The answer is in the same Wikipedia article but I feel the need to mention anisotropies:
Anisotropy /ˌænaɪˈsɒtrəpi/ is the property of being directionally
dependent, as opposed to isotropy. An example of anisotropy is the
light coming through a polarizer. An example of an anisotropic
material is wood, which is easier to split along its grain than across
In general, anisotropies give us an idea about density fluctuations in the early universe which form out the basis(or seeds) of dense matter clusters(galaxies etc) in the universe. How big are these anisotropies(fluctuations)? That measurement is related to parameters of the universe. The answer is in the paragraph above the paragraph you mentioned. This :
The structure of the cosmic microwave background anisotropies is
principally determined by two effects: acoustic oscillations and
diffusion damping (also called collisionless damping or Silk damping).
The acoustic oscillations arise because of a conflict in the
photon–baryon plasma in the early universe. The pressure of the
photons tends to erase anisotropies, whereas the gravitational
attraction of the baryons—moving at speeds much slower than
light—makes them tend to collapse to form dense haloes. These two
effects compete to create acoustic oscillations which give the
microwave background its characteristic peak structure. The peaks
correspond, roughly, to resonances in which the photons decouple when
a particular mode is at its peak amplitude.
Here are necessary details. Some information about the Primordial Density Fluctuations from Wikipedia:
The statistical properties of the primordial fluctuations can be
inferred from observations of anisotropies in the cosmic microwave
background and from measurements of the distribution of matter, e.g.,
galaxy redshift surveys. Since the fluctuations are believed to arise
from inflation, such measurements can also set constraints on
parameters within inflationary theory.
Note that it says, these measurements set constraints on the parameters, i.e. they must be less than or greater than some value. An exact opinion is and was given using different techniques and looking for the common areas in results.
If there's something that bothers you or I was unable to explain well, please mention. :)