In December BroadbandTV DSL decided to dissolve.  I eventually
switched to verizon.net after learning some involuntary lessons about
the relationship of the FCC and the ownership of DLS rights to
telephone lines.

My question is how do I reestablish my email address with dozens of
entities (individuals, corporate, etc.)?  For example, I use to get
frequent email from "CNET Download.com for Mac".  While I considered
much of this as garbage, I wanted to quit it voluntarily not as a
forced amputation.

I know that all I have to do is rejoin these subscriptions but I am
both lazy and often I can't figure out where the link is that allows
me to do so.

Another problem is that I conscientiously registered my software.  I
did this partially so that I could be informed of modifications bug
fixes and whatever.  All of these are now truncated.  I'm sure that
you can imagine similar problems.

By the way, Broadband TV told me that all I had to do send email to
each individual that I had had previous communications.  Fat chance!

I think there are only two options, neither of which is very
promising.  You can either change the stored addresses in all the
various databases that have them ("Fat chance!"), or you can try to
persuade your former service provider to forward your mail
indefinitely.  If they are going out of business, they are unlikely to
be interested in providing this service.  There is some slight chance
that they will sell the domain name to someone who will provide the
service, but I suspect this is not likely.

You can avoid this problem in the future by using an email forwarding
service.  The service accepts mail at a permanent address and forwards
it to wherever your mailbox currently happens to be.  Then if you
change service providers, you only have to change the forwarding
service, not all the database entries that point to the old address. 
There are both free and paid services that do this; I'd be wary of the
free ones, since you want the address to work indefinitely and free
Internet services tend to disappear.

If you just buy email forwarding, your address will be something like
yourname@pobox.com or yourname@akamail.com.  As a more personalized
and expensive option, you could register your own domain name, so it
could be something like you@yourname.com.  Email forwarding is
commonly packaged with domain name registration.  That is, the
companies that offer domain name registration services also often
offer email forwarding for the registered domains.

--efn