Interesting thoughts on spam

[Collins]

My trash box is now receiving up to 200 pieces of spam per day.  Fortunately, 
a few simple filter rules have banished 99% of these from sight.

I used to just delete them as they came in, but then I discovered that nearly 
all the atrocious stuff shared common characteristics:

1. An older form of my email address.  My isp changed the domain name for my 
email about 8 months ago, but continued to forward the old domain to the new 
domain.  No one I value is using the old address, so bang - they're gone.

2. Most of the rest came from subscriptions to two linux user groups that I no 
longer monitor, so bang any mail from these two are gone.

Since the spammers obviously harvested my email address from one or the other 
of these two groups a long time ago, it makes me wonder:

1. Is it really safe to subscribe to any group?

2. Why haven't they harvested my current address?

-- 
Collins