Google Reader appears to be experiencing a number of issues, displaying viewed posts as unread and not allowing users to mark posts as read. Some users are even reporting that several of their subscriptions have disappeared altogether. Judging from complaints on the Google Reader support forum, the issues began sporadically last week, worsened over the weekend, and have come to a head as users return to their daily routine and check their feeds. While some users aren't experiencing any problems whatsoever, we were able to reproduce several of the reported issues. Google support forums contributor Matti Meikäläinen says "the Google Reader team has been notified and someone will be looking into this," but there's no word on how soon a fix will come. We've reached out to Google for comment on the ongoing issues.
Update: We've heard from Google, who informed us in the statement below that the problem has been solved.
"Yesterday, users began noticing issues with Google Reader, which have now been resolved. For everyone who was affected, we apologize for any inconvenience you experienced."