Scammers always try to stay one step ahead of those who fight them, and viceversa. So while security companies were focusing on protecting people's inboxes, a massive increase in the number of malware attacks that focused on instant messengers was recorded in April. According to security firm Akonix, there was well over a doubling in the number of attacks over IM last month.
While attacks through other venues like peer to peer (P2P) software also increased, the increase in IM attacks was well beyond expected. The attacks came from old and new viruses and worms alike. Furthermore, a suggested reasoning for the IM target is that an increasing number of businesses are relying on IM services today.