big mailing lists / slashdotable hosting

[Bill McGonigle]

I'm wondering if anybody has experience running big mailing lists.   
Sure, I run a bunch of mailman lists, but I'm looking at what it  
would take to run a mailing list with a quarter million subscribers.   
(all opt-in, non-spam, properly run).

About the only thing I know is the project will run on linux (or  
maybe BSD, if needed) machines.  There are five aspects I'm thinking  
about:

1) software - I hear mailman can scale that big with a mysql  
backend.  Others wax poetic about mj2.  Lyris is commercial software  
that appears to be big in this space.  I used it a decade ago before  
mailman was groovy for a small list and it seemed fine.  Some, like  
lyris, seem to be built with statistics in mind; mailman appears  
stagnant and threatening to become a Zope app, but there are lots of  
patches for it - support for those patches could be an issue.
2) facility - in-house (bigger Internet connection) vs. co-locating  
vs. outsourcing.  The outsourcing guys seem to want $1-$3 per  
thousand messages or more, which is a nice business to be in, I  
think, but quite expensive per bit.  in-house has advantages as I can  
do things like rate-limiting to reduce the load, but:
3) blacklists - I expect with that many subscribers enough will have  
forgotten they opted in that blacklists will start listing whatever  
server sends mails.  I've seen some pay-for-cartels to gain  
credibility, others have said it takes 30 days for a server to gain a  
good reputation (I have no idea what that means).  Is it a full time  
job to babysit such a list and get off of blacklists?
4) image hosting - the mails will have image links in them because  
apparently lots of people like to see pictures (I always look at the  
text alternative myself...).  I expect to see 100GB or so of image  
traffic, peaking up to 50Mbps.  Can I load this up on a shared hoster  
offering 3TB per month of transfer for $12 or will they kill anything  
that approaches those limits?   I'd like to find a hoster that brags,  
"we can handle a Slashdotting", because this would be large, bursty,  
very intermittent traffic.  Akamai-type solutions look to be too high- 
end for this task.
5) everything else I didn't think to ask

I'd appreciate feedback on any of those items.  If anybody has  
actually done this soup-to-nuts before, I'm interested in hiring that  
person for a short consulting gig.

Thanks,
-Bill

-----
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