Snapchat on Monday confirmed that six billion vanishing videos are viewed daily at the service, in a three-fold surge from early this year.

The highly-valued startup declined to comment on what it thought was powering the rapid growth.

"It (Other OTC: ITGL - news) is a huge number for them," analyst Rob Enderle of Enderle Group said of the Snapchat video viewing number.

"But, you have to be concerned about the nature of the videos; and if they are illicit in nature, a huge number could go away."

The analyst considered it challenging to make money from videos that vanish after being sent from one person to another, instead of lingering for arrays of people to watch the way they do at online venues such as YouTube or Facebook (NasdaqGS: FB - news) .

Facebook revealed during a quarterly earnings call last week that more than eight billion videos are viewed daily at the leading social network, jumping to a level twice as high as it was early this year.

Videos are considered viewed at Snapchat after being displayed for fractions of seconds, while its takes several seconds to achieve that status at Facebook and approximately half a minute at YouTube.

- Stories and replays -

Snapchat's appeal has been the promise that messages shared disappear shortly after being viewed, providing users a sense of being able to keep pictures or videos private and ephemeral.

Snapchat last month introduced a "replay" feature for those disappearing messages, giving users an option to get another look at three "snaps" for a fee of 99 cents.

The feature was the first by the Los Angeles-based social network to get revenue from its user base in addition to advertising messages.

Snapchat in May said it raised $537 million in a new round of equity funding.

The vanishing-message service did not disclose who bought stakes in the Los Angeles-based company, which came at a price estimated to give Snapchat a value of more than $15 billion, according to media reports.

Snapchat rejected a $3 billion takeover offer from Facebook in 2013.

Snapchat rocketed to popularity in the United States, especially among teenagers, after the initial app was released in September 2011.

The smartphone app late last year began letting users in the United States send money to friends by simply typing dollar amounts into new "Snapcash" messages.

The new feature came from a collaboration between Snapchat and Square, a mobile payments company headed by Twitter (Xetra: A1W6XZ - news) co-founder Jack Dorsey.

Snapchat also added a "Stories" feature that strings together a series of "snaps" to create a narrative that is available for repeated viewing by recipients for 24 hours (Other OTC: UBGXF - news) .