Spamhaus has published a list of the world's 10 worst spammers. And with inboxes bursting full of Viagra offers, penis pumps and sexual performance enhancers, is it really any wonder that they are all men?

It's Register of Known Spam Operations (ROKSO) database -- which is used by ISPs to avoid signing up known spammers, and by law enforcement agencies to help with investigations and prosecutions -- features four Russians, two Americans, an Israeli, a Canadian, a Hong Kong resident and at the very top of the list, Ukrainian, Alex Blood.

Blood, who also goes by pseudonyms, Alexander Mosh, AlekseyB and Alex Polyakov, headlines the list for disseminating child porn spam though the use of his army of botnets. He is also associated with a Russian spam gang called Pavka/Artofit.

The report also reveals that around 80 percent of spam that targets Internet users is generated by a small hardcore group of no more than 200 professional spam gangs.

The offences committed by the spammers include sending a variety of junk such as porn, penis pills, loans, financial scams and proxyhijacking.

Spamhaus claims the internet continues to be plagued by spam as a small number of large ISPs sell services knowingly to professional spammers for profit, or do nothing to prevent spammers operating from their networks.

Spamhaus also keeps a top ten list of those networks it says are responsible for delivering most spam. They are:

1. verizonbusiness.com
2. serverflo.com
3. sbc.com
4. xo.com
5. proxad.net
6. rr.com
7. tpnet.pl
8. edu.tw
9. hinet.net
10. ttnet.net.tr