The death of Michael Jackson has had an immediate impact on his sales.

Five of the top ten "trending topics" on Twitter are currently Jackson-related and his death dominates Google trends.

The singer dominates the U.S. iTunes store's top albums rankings, with seven sets in the top 10 today.

At 2pm BST on iTunes U.S., "The Essential Michael Jackson" was No. 1, followed by "Thriller" at No. 2, "Number Ones" at No. 3 and "Off The Wall" at No. 4. "Thriller (25th Anniversary Edition)" was at No. 5, with "Bad" at No. 9 and "The Ultimate Collection" at No. 10.

Jackson also had eight of the top ten music videos on U.S. iTunes, including U.S.A for Africa's "We Are the World," with Thriller at No. 1.

On Amazon.com, the Sony Music Entertainment album catalog and hits sets had the top 15 positions on the site's best-selling music chart.

Sales are likely to surge in European territories throughout the course of the day, where people woke up to the news of the singer's death. By 2pm BST, Jackson has eight of the top 10 selling albums on the U.K. iTunes store.

U.K. entertainment retailer HMV has reported a huge surge in sales.

"We have seen a huge outpouring of affection for Michael - we haven't seen anything like this since John Lennon and Elvis died," said a statement. "HMV stores around the country have had crowds of fans and general members of the public coming in all day to buy his classic albums and hits compilations - and some have even left with multiple copies.

"We estimate there has been a 20-fold increase in demand for his recordings, which means we may well see some of his classic hits back in the charts again, especially as our digital store at hmv.com is reporting recording numbers of downloads of Jackson tracks."

Jackson's death is likely to have an impact on the U.K. charts on Sunday (June 28). According to the Official Charts Company, Jackson has some of the biggest-selling albums in the U.K., with his top five sellers almost totaling 13 million sales.

"Thriller" has moved 3.9 million copies, while "Bad" has sold 3.6 million. His other biggest sellers are "Dangerous" (2.2 million), "Number Ones" (1.6 million) and "HiStory" (1.5 million).

In Australia, where news broke on the morning of June 26, Jackson had five sets in the top 10 albums on the country's iTunes store.

The BBC reports that both Google and Twitter were both overwhelmed by the volume of people using each service. Some Google News users briefly experienced difficulty accessing search results.