6 cool innovations we're still waiting for

Flying cars were always a pie-in-the-sky proposition, but hologram calls and many other bold tech ideas have hit snags.

Spam-free inboxes

tech broken promises gmail spam

The hope: "Two years from now, spam will be solved," Bill Gates proclaimed in 2004.

The reality: Er, not so much. According to Gates' own Microsoft (MSFT), spam accounted for an astounding 97% of all email sent in 2008. The anti-spam technology has improved somewhat, but progress is slow: 71% of last month's email was spam, says Kaspersky Labs.

What's the deal? As spam-blocking technology becomes more advanced, so do the spammers.

"These days, spam is moving into a realm of truly professional development," said Christopher Budd, threats communications manager at Trend Micro (TMICY). "Some spammers are even hiring editors to make sure their English is good."

Budd pointed out that any security system has limits. Spammers are cooking up increasingly more technical ways to infiltrate victims' computers, and spam-blocking technology has to catch up.

So a completely spam-less world will likely never come to pass -- and you should still delete that email from the prince of Nigeria.

  @julpepitone - Last updated April 02 2013 06:26 AM ET

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