The popular blog hosting service TypePad remained offline Friday morning, with one message on the site claiming it was undergoing maintenance while another said that it was "working diligently to restore access."

TypePad, which is a for-fee hosted version of Six Apart Software's Moveable Type blogging software, has experienced numerous problems recently, and after some prominent bloggers threatened to take their tomes elsewhere, apologized in October for lousy performance. Friday's outage, however, was the most serious yet, with the outage expected to run 12 or more hours.

Existing blogs are up and viewable, but have been restored from backups that are two or more days old, meaning that the newest content is missing. Posting and commenting are unavailable.

"We were doing routine maintenance on our main storage system at around 11 p.m. Thursday," said Jane Anderson, a spokesperson for Six Apart. "That machine went offline, and now we're in the process of bringing it back up."

Full access to the service might be restored by mid-day Friday PST, or at the latest, during the afternoon. Restoring the newest backup copies of blogs, however, will take longer.

Anderson also said that the San Francisco-based company had e-mailed customers with an offer to compensate them for the outage, but had, she said, "asked them to name their own compensation, since this has affected some bloggers more than others." Six Apart gave customers the choice of no compensation, or credits for 15 days, 30 days, or 45 days of service.

According to Anderson, about a third of the responses received from the e-mail had asked for no compensation. TypePad charges between $5 and $15 a month for the blogging service.

TypePad wasn't the only blogging host to report problems. On Wednesday, for instance, Bloglines admitted poor service, saying on its site that "we're not going to beat around the bush about this…Bloglines performance has sucked eggs lately."