A 27-year-old man described as one of the world’s most prolific spammers was arrested Wednesday, and federal authorities said computer users across the Web could notice a decrease in the amount of junk e-mail.

Robert Alan Soloway is accused of using networks of compromised “zombie” computers to send out millions upon millions of spam e-mails.

“He’s one of the top 10 spammers in the world,” said Tim Cranton, a Microsoft Corp. lawyer who is senior director of the company’s Worldwide Internet Safety Programs. “He’s a huge problem for our customers. This is a very good day.”

A federal grand jury last week returned a 35-count indictment against Soloway charging him with mail fraud, wire fraud, e-mail fraud, aggravated identity theft and money laundering.