The terms SnowShoe Spammers is well explained on the Spamaus Site in this article about snowshoe spam.
Like a snowshoe spreads the load of a traveler across a wide area of snow, snowshoe spamming uses many frequently-changing IP addresses, domains and aliases to spread out the spam load in order to dilute recipient reputation metrics and [...]

Ok, all the affiliate spammers claim that we/you have subscribed to their mailings.  We have been receiving the affiliate spam to email addresses that NEVER ever subscribed to anything, those email addresses were posted on various web properties for our customers as contact us email addresses and now are plagued with onslaught of UCE.
The affiliate [...]

The following domains transmitted UCE SPAM to our servers, domains were black listed.

stimulatinghomesalary.com
Greedy Cell Phone/Wireless Comp. Glitch creates Huge Cash Flow. Learn-Earn within Hours.

spectaculardive.com
Get Informed on Swine Flu.

lawyerjohnonline.com
Need self-employed health insurance? Find good coverage.

thefederalpaper.com
Discount printer ink and toner plus 10% coupon

erlangorchid.com
Take the First Step

skynormas.com
Do You Know How to Prevent H1N1 Flu?

irisboot.com
Your attention is [...]

Here is a fresh list of domains who transmitted UCE Spam to our servers on 5-18-2009
The domains who sent spam to our servers on 5-17-2009 have been blocked, so this is a fresh list.

tiltimesh.com
$48,506.66 In 4 Weeks From Scratch With

fruitwhite.com
$500 JetBlue Gift Card for You: Details Inside!

flowerviolet.com
$500 JetBlue Gift [...]

Niche Marketers Network
14545 J. Military Trail #137
Delray Beach, Fl 33484
identified themselves as marketer of the UCE SPAM message, the original link in the spam mail was to a web address

ropespice.com/gqxpngrpjosuwlmnfq
which redirected to this website
www.littlelimabeanone.com/22968/?AFID=13365&SID=CD14790
so the marketing via UCE SPAM is done for these attorneys by affiliate ID 13365
….  the Spammer uses  many other web [...]