“They spent a ton of money on this thing and it is natural they want to make a return,” analyst Rob Enderle of Enderle Group in Silicon Valley said.

Google has bided its time working on ways to “monetize” YouTube without alienating notoriously transient Internet users that could easily switch to Hulu, Daily Motion or other rivals in the online video-sharing arena.

“Click-to-buy” links are being discretely placed in control panels below YouTube videos to invite people to visit online shops iTunes or Amazon.com to buy music, books, films or other material related to snippets watched.

“This is just the beginning of building a broad, viable e-commerce platform for users and partners on YouTube,” said a message on the website.

“Our vision is to help partners across all industries offer useful and relevant products to a large, yet targeted audience, and generate additional revenue from their content on YouTube beyond the advertising we serve against their videos.”

Links to online stores are making a U.S. debut on videos of EMI Music artists and of the Spore computer game recently released by Electronic Arts.

All tracks are now available in MP3 DRM-Free format, which allows the music to be downloaded from any device. The change comes ahead of UK rivals Amazon, HMV and Tesco, which are also poised to offer DRM-Free downloads.

PlayDigital was launched by the pure-play entertainment e-tailer for the first time in February with the support of EMI. Sony BMG, Warner Music and Universal Music have now come on board and there are more than 3 million tracks available for download.

Head of PlayDigital Wendy Snowdon said: “It was only a matter of time before the other three major labels came on board and we now have an offer to rival that of iTunes, yet in a format that gives the customer choice and at a more appealing price.

“PlayDigital has been a phenomenal success since its launch and now, armed with a full back catalogue and current releases from all the majors, we are fantastically placed to take a bigger bite of the apple.”

As Play has offered for a while, the top 100 songs on the store will be offered for 65p per track, with some albums as low as £4.99, including the brand new Oasis album, Katy Perry’s debut, and albums that aren’t rumoured to cause cancer because they’re so bad.

But Play.com isn’t the first to achieve this admirable milestone. 7digital was the first European store to offer MP3s from all major labels as of a few weeks ago. Also, in the US, Amazon’s MP3 store has had all the majors on board, sans-copy protection, for months.

Obviously, MP3s are the format of choice for the majority of consumers when it comes to downloading, as they’ll play on any MP3 player, any  iPod, any phone, and can be freely burnt to CD for use in other music systems, just like a normal CD.