Hot topics in the tech blogs for the week ending July 23 include Facebook reaching an important milestone, tech companies posting their quarterly results, Windows Phone 7 previews, the launch of a social magazine for iPad, and e-book sales outpacing those of hardcover books.

Facebook reaches 500 million users
Social networking site Facebook reported it had 500 million active users this week. To celebrate the important milestone they launched a new application called Facebook Stories. The company encouraged its 500 million users to share stories about the impact the site has had on their lives. Facebook's pending legal suit with a man who claims to own 84 percent of the company has also dragged Facebook's name into the headlines this week.

Record quarterly reports
Both Apple and Microsoft posted record quarterly results this week. Apple's revenue increased by 78 percent in its second quarter thanks to strong sales from their iPhone and iPad product lines. Microsoft too was positively glowing after announcing a 50 percent increase in profits and defying predictions that Apple would surpass the company in revenue this quarter.

Windows Phone 7 previews
Earlier in the week select bloggers got their hands on brand new Windows Phone 7 devices. "Welcome back into the smartphone arena Microsoft, it looks like you have a serious challenger entering the ring," wrote ZDNet's Matthew Miller after going hands-on with the device. Engadget's Joshua Topolsky wasn't quite as overwhelmed. He commented, "What we've been presented with here doesn't exactly feel like a complete mobile operating system in many ways."

Bloggers got excited about a new "social magazine" iPad application called "Flipboard." The app, which aggregates and presents users' Twitter, Facebook, and news feeds in a digital magazine-style layout, was quickly dubbed the world's first "social magazine" and given a healthy lathering of praise. However, the positive reviews also resulted in the company being overwhelmed with new users on its first day and some blogs also questioned the legality of an application that "scraped" articles and pictures from other sites.

Amazon e-book sales exceed hardcover sales
Online marketplace revealed that during the last three months, sales of e-books had eclipsed hardcover book sales. In the last month for every 100 hardcover books sold on the site, 180 e-books were sold. Amazon itself said the trend is "astonishing when you consider that we've been selling hardcover books for 15 years, and Kindle books for 33 months."