Reuters is reporting today that Penguin has bought the content of Catherine Sanderson’s blog, La Petite Anglaise, to publish it in book form. The acquisition is now the most hotly-discussed topic at the Frankfurt Book Fair.

Penguin’s publisher, Katy Follain, commented: “The blogs should be almost incidental to us as publishers. We need to look at the writing itself. Her writing is so strong we signed her for two books.”

A mid-six-figure sum has been floated as the advance on Anglaise.

Rival publisher, MacMillan’s Chief Executive Richard Charkin writes on his own blog : “I’m not quite sure what a mid-six-figure sum is, but let’s imagine £500,000 ($942,700) and let’s assume that non-UK rights are about the same. It means that the book will have to sell around a million copies to earn back the advance.”

Reuters reports : “Some blogs-turned-books have been hits with readers, but publishers could not recall any that had reached such a lofty sales tally.”

Indeed many have had disappointing sales because the immediacy and transient nature of blog posts don’t sit well with the permanency of the book format. Blogs that translate successfully into books, are usually written as books by book authors, or at least rewritten for a different medium.

It’s interesting that Penguin’s publisher says that the blog is irrelevant, it’s the quality and strength of the writing that counts.

Blogs have a very different presence to that of books. In some cases, they’re closer to newspapers. Reportage blogs do very well if written by a well-informed and intelligent journalist. Most blogs, though, more easily resemble magazines, having content that’s useful and less transient than the newsy outfits.

The big publishers clearly know what they’re doing here — more so than the bloggers. They will have to invest a significant sum of money to publish a blog in print. They can’t afford to be impulsive amateurs.

As I’m often saying these days, blogs can be many things. It’s important to know what.