I do SPAM reporting with Purify on a very frequently base, and I get a lot of "response":

1. Abuse address does not exist

Example:
abuse@clearwire.com on Sun Jan 20 09:54:32 2008
The e-mail account does not exist at the organization this message
was sent to.

2. Delays

Example:
Delivery to the following recipient has been delayed: ip@krnic.kornet.net

3. Rejected because of SPAM

Example:
Delivery to the following recipient failed permanently:
www@dkm.cz
Technical details of permanent failure:
PERM_FAILURE: SMTP Error (state 16): 554 mail server permanently rejected message, spam detected (#5.3.0)

and so on ....

Only the few big companies (like verizon) accept the abuse reports, but I'm sure that nobody there will ever take a look at them, so I think that almost 80 to 90 % of all my reporting run into digital nirvana.

Question: Why should we continue wasting time on reporting?

I'm looking for a really good reason.

You bring up valid points Thomas!

Tycho recently made a post advising that he has noticed a dramatic decrease in his spam level as a result of his reporting effort. To me, this is the only valid reason to report.

The cold hard truth is, your mileage may vary. If you are getting 80-90% of your spam from infected Windows computers, especially from countries with loose spam laws, then reporting is probably going to be a waste of time for you. I would focus every minute of your time on developing your filter. With the import/export feature, I'm hoping that there'll be more sharing of blacklists.

With my filter setup, my spam problem is gone. I get between 3-5 that get through my filter each day, tops. And these are usually frivolous emails that serve no purpose (have no links, are just garbage).

You have been reporting long enough that you should absolutely have noticed a dramatic decrease in your spam level. If you haven't, then I would stop wasting time on reporting, and focus on filtering. My two cents.