Apple has begun extending the length of song samples from 30 seconds to 90 seconds at the iTunes Store in the U.S. Many samples of the site's top-selling singles -- such as The Black Eyed Peas' "The Time (Dirty Bit)" and Coldplay's "Christmas Lights," -- are available in the longer format, reports "CNET" (http://news.cnet.com/8301-13579_3-20025106-37.html?part=rss&subj=news&ta...).

The length of song samples has been found to be key to a consumer's decision to purchase music online, the article adds. Researchers at Robert Morris University reported last year that consumers were more likely to buy songs if allowed to sample the music for about 60 seconds and if provided access to a "high-quality" version of the music.