QUESTION: Does the Nexus 7 tablet need a security application like Norton or McAfee on it? If so, what apps do you recommend?

--Debbie, Amelia Island, Fla.

ANSWER: The Nexus 7, which runs the Android operating system, is part of a booming ecosystem of mobile devices that can certainly fall prey to malicious hackers.

But despite the very real threat, recommending a security solution for your portable gadget is a little more difficult than for your desktop.

When it comes to the latter, there's a common refrain I hear from my go-to geeks: Keep your system updated. Use shrink-wrapped antivirus software. Avoid downloading things from unfamiliar sources.

These tips don't exactly correlate to tablets and smartphones.

System updates are often out of users' hands, antivirus software is only available through centralized app markets, and with so many quality startups making apps, the "unfamiliar source" rule isn't a terribly good guiding principle for mobile.

There's also evidence that antivirus apps, in general, are having an incredibly hard time keeping up with the rapid pace of mobile malware evolution.

Researchers with North Carolina State University's Android Malware Genome Project collected and analyzed 1,200 samples of malicious mobile software that hit the market between August 2010 and October 2011. Their research showed the number of new malware families in July 2011 -- just one month -- beat out everything they had collected in all of 2010.

With their samples in hand, the N.C. State team also tested the effectiveness of four mobile antivirus apps: AVG (free to $14.99), Lookout (free to $2.99/month), Norton (free) and TrendMicro (free).

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