Welcome back to the second edition of the Walker Sands Friday Five. Here are our picks for timely stories in tech, business-to-business marketing and public relations from the week.

Friday Five for the week of July 16-20, 2012:

1. Tablets, Smartphones Still Hammering PC Market

(CIO)

Although the tablet and smartphone markets continue to become more segmented, it’s clear that they’re still managing to drive sales far above the PC market.

2. Facebook Earns 58% More Per Ad Than Last Year, Mobile Ads Clicked 4X More Than Twitter Ads

(TechCrunch)

Social engagement is up, and so is Facebook ad revenue. Cost per impression is up by 58% compared to last year.

3. Power List 2012

(PR Week)

PR Week's 2012 list of top names in PR highlights the individuals propelling public relations to unprecedented heights.

4. Mining Marissa Mayer's Googly Past For A Glimpse at Yahoo's Future

(Fast Company)

How will Marissa Mayer lead Yahoo as CEO? Fast Company takes a look back at Mayer's interviews to explore potential directions.

5. Mobile Marketing Lags in China, World's Biggest Cell Phone Market

(AdAge)

With the high volume of cell phones in China, one would think the country is a hot spot for mobile marketing. However, eMarketer found mobile's share of total ad spending in China is about only 1.5%.

Have a great weekend and check back next Friday for a new edition!