Microsoft is moving forward with its policy to restrict access of free Xbox Live downloads, including select demos and in-game content, to Xbox 360 owners with a paid Xbox Live Gold subscription. Those who have a free Xbox Live account, commonly referred to as Silver, will not be able to access the content until it has been available for a week.

The recently released downloadable content for Irrational Games' 2K Boston and 2K Australia's BioShock (PC, X360) is the latest example of the policy, which was first introduced with the 2006 debut of a promotional advertisement for Epic's Gears of War (PC, X360) that was available only to Gold subscribers for a limited time.

"This is going to happen more and more (Gold getting things before Silver)," Xbox Live director of programming Larry "Major Nelson" Hryb wrote at the time, "so you may want to think about upgrading if you want all the latest and greatest trailers, demos etc."

Yesterday's Xbox 360 system update contained new functionality to point out what Silver members can and can not download. Restricted content is marked by a red circle with a slash through it, and an attempted download brings up an error message advising Silver account holders to "check again in a few days or upgrade to an Xbox Live Gold Membership."

Though Silver members can create an online friends list and have access to the Xbox Live Marketplace, which offers up a number of free and premium-priced downloads, they are not able to play online with other Xbox Live members. That privilege is restricted for Gold-level access, which runs $7.99 a month, $19.99 for 3 months, or $49.99 for 13 months.

"This is not done to annoy our Silver members," stated Hryb. "Limited time exclusive access to content is just one of the many benefits of having a Gold Xbox Live account."