Each day, Inc.'s reporters scour the Web for the most important and interesting news to entrepreneurs. Here's what we found today.

Annals of bad product design. There's a fun conversation happening on Quora about the worst product design of all time. The nominees include such ubiquitous products as umbrellas, bras, cigarettes, and sofa beds, as well as some easy-to-hate standards such as impenetrable plastic clamshell packaging, the Florida butterfly ballot, the CueCat, and the RJ-11 phone jack. Apple's forgotten 'puck' computer mouse, Google Wave, and the Hindenberg zeppelin also rate mentions. (We would submit that, as disasters go, these were not equivalents.) What would you nominate and why? Let us know in the comments section below.

Facebook launches Deals. If you're in one of Facebook's five chosen cities, you've got some bargains to take advantage of.  The social site has introduced its new feature called  Deals, which allows users in Atlanta, San Francisco, Austin, San Diego, and Dallas to receive discounted offers on products and services via e-mail and news feed. With the frenzy of daily deal sites on the market, we wonder if people will bite. What do you think?

Is the sharing economy just a fad? Derek Thompson over at The Atlantic ponders the business of sharing, and how it relates to the U.S. economy. "The Web has built windows into millions of families' homes and garages and let rent-happy customers ask, 'Hey, can I use that for a second?'" he writes. "If those millions of families keep responding yes, we're on the verge of an exciting new chapter in American consumerism." Start-ups like Neighborgoods and ThredUP already allow people to share, and if these start-ups start getting national traction, it's possible Thompson could be onto something.

TapJoy caps its apps. Hard as they try, the little guy still can't pull one past Apple. TapJoy, an app-based startup that allows companies to pay-per-install, announced yesterday that it is putting a limit on the number of installs each user can make, MocoNews reports. TapJoy serves app developers looking to gain popularity by boosting their rankings in the App Store's lists of top applications, the only real way to gain recognition in Apple's discovery system. Apple, not happy with the manipulation of their system or having their discovery weaknesses exposed, began rejecting updates to applications that use such marketing programs last week. TapJoy is likely changing its tune now to avoid a similar fate. While it would probably serve Apple well to fix the glitches in app rankings rather than stamp out companies capitalizing on them, Apple won't loosen its grip on the app empire anytime soon.

A surprising workplace problem. Time.com's "Healthland" blog offers this alarming statistic: Nearly 80 percent of adults in the U.S. will call in sick to work because they suffer from lower back pain. The good news is that back pain can be alleviated in a variety of ways, with effective treatments including physical therapy, regular stretching, massage, acupuncture, and Egoscue. Alas, Time.com notes that many employer-sponsored health plans don't cover these treatments even though some 95 percent of back pain sufferers report that various therapies healed them.

Superlative start-ups of the Summit Series. Similar to the annual TED event, the Summit Series engages the best and brightest business minds through curated events. This year's series, called "Summit at Sea," packed a cruise ship full of 1,000 young and brilliant (and rich?) entrepreneurs, artists, activists, and musicians—including billionaire Richard Branson, music producer Russell Simmons, and musical group The Roots—and set sail to a private island off the coast of Miami. Out of all the creative ideas shared over the course of the epic three-day event, and The Huffington Post chose the four most exceptional, innovative start-ups from the Summit Series that best exemplified the spirit of the event.

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