On Monday, while China Web watchers were digesting the latest bit of news on the requirement that PCs sold in China include government-mandated Internet filtering software, the Web as we knew it a week earlier quietly returned.

On June 1, at around 5 p.m., Internet users across mainland China began reporting problems accessing popular social networking sites, such as Twitter.com, the Yahoo-owned photo-sharing site Flickr.com, and Microsoft's Live.com, Bing.com and Hotmail.

The sudden unavailability of these sites led many Internet users to suspect that they had been blocked due to sensitivities over the 20th anniversary of the Tiananmen Square crackdown on June 4. And on June 3, dozens of Chinese Web sites also announced that they would be closed for technical maintenance for several days.

Now, it looks like most of these sites are back, though some popular sites that were inaccessible before last week remain so.

These include blogs hosted on blogspot.com and the video-sharing site YouTube.com, which has been unavailable for several weeks. Blogspot and YouTube are both owned by Google.

• Click here to read the rest of this story in the Wall Street Journal.

• Click here for FOXNews.com's Personal Technology Center.

• Got tech questions? Ask our experts at FoxNews.com's Tech Q&A.