According to Brad Taylor, software engineer at Google’s Gmail, the number of ads hitting our PCs may soon start to fall for the first time in years.

Taylor bases his theory on the fact that the amount of spam sent to email users is levelling off.

Although he wouldn't release any figures, Taylor told Wired magazine that the percentage of spam email sent through Gmail waned over the last year.

And having overseen Gmail's spam filter since the service launched in 2004, he should be able to spot a downwards trend.

While that’s good news for Gmail users, it may not be great news for all email users, according to web security company ScanSafe.

Mary Landesman, security analyst at ScanSafe, told Vnunet.com that the success of Gmail's filtering policy may have led spammers to attack other targets.

"Spammers are interested in the bottom line and the return on investment for a spammer is the percentage of open rates that result from any spam campaign," she said.

"It is certainly possible that the open rates for Gmail targeted addresses have not been as successful, such that Gmail is being slightly less targeted as a result."