Kim Kardashian, Amber Portwood Climb Internet Buzz Chart

May 21: Kim Kardashian attends the 16th Annual Cosmetic Executive Women Beauty Awards at the Waldorf-Astoria in New York. (AP)

Which celebs were up and which were down on the Internet this week?

Keeping tabs on the always-entertaining world of entertainment news, GossipCenter.com tracks celebrity online popularity 24/7 with their Gossip Center Hot 45 List.

Maintaining her status as a dominant web presence, Kim Kardashian reclaimed the top spot on the Hot 45 list after slipping to the No. 2 ranking (the horror!) the previous week while Katy Perry and Lindsay Lohan filled out the Top 3.

Let’s see how this all played out.

Always one of the hottest searches around, Miss Kardashian’s latest attention-grabbing efforts got an early start as she immersed herself in the NBA All-Star weekend happenings while joined by New Jersey Nets beau Kris Humphries. Among the stops, the duo hit up Kevin Hart's "Laugh At My Pain" Official NBA All-Star After-Party as well as the Ciroc Vodka NBA All-Star weekend fete. The E! reality star also made headlines upon industry rumors telling that she’s in talks to star alongside John Travolta as Kim Gotti in an upcoming biopic about New York mafia don John Gotti.

Following closely behind was “Firework” hitmaker Katy Perry, who managed to draw the public’s interest as she launched her European Tour in Lisbon, Portugal, while also offering up an energetic Milan Fashion Week kickoff concert and lashing out at tabloids over their attempt to incite a feud between herself and Britney Spears.

Expectedly placing upwards on the Hot 45 List was troubled actress Lindsay Lohan, who claimed the third position as she made her much-awaited court appearance for charges of grand theft – as she’s accused of lifting a $2,500 necklace from a west coast jewelry store. The matter was continued to March 10th, with the judge sternly warning the “Mean Girls” starlet that a plea deal will result in jail time.

As for the movers and shakers, Nelly shot up from obscurity to garner the sixth slot as fans went wild for shirtless beach pics of the St. Louis rapper shooting his music video “Gone” on the beach in Mexico with Kelly Rowland. Also on the up and up was “Teen Mom” star Amber Portwood, who had the unfortunate experience of seeing nude private photos of herself land in the wrong hands and on the web.

On the other end of the spectrum, Lauren Conrad slowly but surely descended the ranks of the Hot 45 List – as the former “Hills” star wound up perched in 92nd after hovering around the top ten the previous few weeks upon word of the cancelation of her MTV reality show and celebrating her 25th birthday with a stylish bash held at Pure nightclub in Las Vegas.

Those are this week's movers and shakers. Check back next Friday to see how your favorite celebrities fared. And click here for the complete Gossip Center Hot 45 List.

The Gossip Center Hot 45 List is calculated by looking at the popularity of the site's hottest stories, and determining which stars are on the rise, and who is crashing and burning. All of the articles, pictures and videos on the Gossip Center Network are scanned for activity, and the rankings are updated several times a day.