Personally, I believe that the more advanced filtering should be left
to the client that recieves the results, to relieve the search
algorithm a bit.

I think the search syntax must be as powerful as possible to reduce network load (for both clients and hubs).

I would also _love_ to see regexp searching, but I guess the Windows
folks won't be too fond of that. If it would come to pass, I would use
a SRCH command like this instead, where all parameters are always
"and"ed (removing comparison groupings do relieve clients a lot, as
well):

I also agree, regexp is cool :) but I also think windoz users are more familiar with standard windoz wildcards.

SRCH N~(.mpg|.avi)$ S>350M S<700M

For those who aren't used to regexps, they also allow some pretty
interesting stuff. For example, take a very popular series like Ranma
1/2, which has lots of variants. If I want to search for episode 5 of
season 4 and want to avoid sizes below 100MBs (to get rid of the
dubs), I could use this to make sure I get the right one:

SRCH N~ranma[^0-9]*4[^0-9]+0?5[^0-9]*.avi$ S>100M

<very serious mode>
Why not using something more powerful like expression that can be processed by perl ( you are not very far with your N~ and S> ). Only few things are missing like &&, || or parenthesis.
</very serious mode>

With this, I agree to vote for your protocol :-)

Eric