Rep. Anthony Weiner in Sept. 2010/credit: Corbis

The Pew Internet and American Life Project recently published a new survey showing a 5 percent bump in Twitter usage since November, just as the social networking site had been making headlines in connection with Rep. Anthony Weiner.

As the Twitter population rises, the potential public impact of those 140-character messages arguably increases as well, especially for notable users with large followings, such as Rep. Weiner, who resigned as a result of getting caught sending raunchy photos via Twitter.

A quick recap of the New York congressman's Twitter woes: Around 1 a.m. on May 28, an image captured on the Twitter photo application yfrog was tweeted out from Rep. Weiner's account. The snapshot showed a close-up of a man's underwear-clad crotch, and the tweet tagged a young woman Weiner follows on his account.

Around four minutes later, the lewd tweet disappeared, and Weiner casually messaged out the following:

"Tivo shot. FB hacked. Is my blender gonna attack me next? #TheToasterIsVeryLoyal."

But in the age of Internet non-privacy, that deleted tweet certainly didn't disappear. In fact, more lewd Internet exchanges with other women began to surface. A week later Rep. Weiner admitted he had lied and had, in fact, sent the lewd tweets. Today, the 46-year-old congressman yielded to pressure from top Democrats, saying he would step down.

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"Weinergate," as the controversy has been dubbed, serves as a worst-case-scenario example of tweeting in the public eye.

Weiner has more than 60,000 followers (the media flurry has tossed him around 15,000 additional followers in the past week), yet he only follows 198 people back. Naturally, when public figures have a swarm of Twitter fans and elect to follow only a fraction, it may attract additional scrutiny to those chosen few.

In Rep. Weiner's case, for instance, the media questioned why he was following this college student (706 followers), as well as porn star Miss Ginger Lee (4,313 followers).

For public figures with a manicured image to uphold, Twitter can be risky business. On the one hand, people enjoy candid tweets from famous folks, allowing them to feel connected on a more personal level. On the other hand, off-the-cuff tweets can land some people in trouble, causing them to have to backtrack and explain misspelled or nonexistent words, flagrant emotions, and unnecessary personal details.

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Moreover, the Twitterverse simply pays more attention to public figures' tweets, whether they're casual asides or polarizing statements.

Recent Twitter analysis from Yahoo! Research found that around 50 percent of the tweets read by the Twitterati are produced by only around 20,000 "elite users" (celebrities, politicians, popular bloggers, etc.). So while more than 105 million people are chirping away on Twitter, the masses are only listening to a small minority of voices.

Consequently, public figures should tweet carefully because those 140 characters can have enormous ripple effects –- both positive and negative. For instance, pop star Miley Cyrus possibly found a new group of left-leaning fans when she tweeted last week about boycotting retail chain Urban Outfitters for political reasons. And of course, those tweets could also cost her fans on the other end of the political spectrum.

Without public relations experts carefully crafting those micro-blog updates, public figures should weigh the costs of going rogue on Twitter and type thoughtfully. Yet it's a risk that many deem necessary, since staying relevant often means staying actively engaged in social media.

Case in point: Anthony Weiner. The New York representative did not quit tweeting since the crotch shot began ricocheting around the blogosphere and media outlets.

Even Gennette Cordova, the college student tagged in the nefarious tweet, has gotten back on the social media network with the new tagline, "I can't believe I'm back on Twitter."