I still have a hard time to figure out on how the major camera
companies place their product in the market. Are their product names
and series designed on purpose to confuse the consumers? Or are they
as confused as we are (in trying to sell products which cover our vast
budget range)? Reviewing a variety of products will become difficult
for the consumers.
Can anyone explain or may be can direct me to a website, which may
provide information behind the naming of the products and series? Do
lower numbers refer to older models, cheaper price, lower features or
all of the above? Examples as follows

Canon cameras:
Powershot series : What are the difference between A,G,S,Pro,SD and TX
series? I know that SD is the ultra compact, TX has camcorder vertical
style, A series using regular AA batteries? How does G7 compare to S3
IS and Pro series? Why SD1000 camera is cheaper than SD900?
Digital series : Are EOS ( 5D,30D, etc) series are superior that
Digital Rebel series (XT, Xti) ? Are EOS series designed for
professionals?

Nikon Cameras:
Powershot series : What are the difference between series L, P, and
S? Is the new Coolpix P5000 similar to Coolpix 5000 introduced much
earlier? Is Coolpix S9 has better features, and more expensive that
the Coopix S5? Is P5000 Nikon best offer to compete with high end
powershot camera (rival to Canon G7)?
Digital series: Is the D200 the new ultimate digital camera produced
by Nikon? How does it compare to the older D1 or D1H introduced in
the early 2000s?

Panasonic/Lumix cameras:
Powershot series : What are the difference between series FX, FZ, LX,
LC, LZ and TZ?
I found the Panasonic series are even worse than Canon in term of
trying to compare with. LZ series is the bulky one. What series is the
ultra compact one? Is it LC series?
Is the FZ50 currently the top of the line of the powershot series?
How is this compare to Lumix LX2, for example? Does Lumix produce
product similar to Canon G7?
Only one digital product, which is L1 - so, no comparison.

Thanks for info.