I have had SPAM from them too, In fact I have repoted to SPEWS.
Here is some info on them and to find out who they are:
PD Host Inc
Vanterpool Plaza, 2nd Floor, Wickhams CAY I
Phone: 1 415 8747218
Domain Name: TRAFFICMAGNET.COM
Created on..............: Wed, Mar 06, 2002
Expires on..............: Mon, Jan 21, 2013
Record last updated on..: Thu, Jul 17, 2003
Domain servers in listed order:
Domain Name: ELINKDNS.COM
Registrar: ENOM, INC.
Whois Server: whois.enom.com
Referral URL: http://www.enom.com
Name Server: AXN.ELINKDNS.COM
Name Server: TONGYAN.ELINKDNS.COM
Updated Date: 17-jul-2003
Creation Date: 13-jul-2003
Expiration Date: 13-jul-2004
Pdhost.com uses same as above too (no need to paste it all).
Thier IP 18.104.22.168:
ARIN says that this IP belongs to APNIC; I'm looking it up there.
inetnum: 22.214.171.124 - 126.96.36.199
descr: CHINANET Beijing province network
descr: Data Communication Division
status: ALLOCATED NON-PORTABLE
They seem to be in SPEWS Listings already :
Guess a few more complaints won't hurt