I have often wondered how full-time professional journalists managed to earn a living from weblogs – today one of the top US-based bloggers Andrew Sullivan explains it all — they don’t.

Sullivan produces a high-quality site full of his well-written and articulate conservative views, a far cry from the rabid warblogs I have complained about elsewhere, but he is now asking for donations to help him carry on producing the site. His idea is a pledge week, with regular readers donating $20 each to help make it slightly worth his while to carry on blogging.

“If we succeed this week in providing a financial basis for the next year, I’ll keep on bloggin’. If we don’t, I’ll have to rethink. I simply can’t do what’s becoming a full time job for nothing any more. And I really want to avoid making people pay for the site, through a toll-booth or paid-only access. After two years of voluntary work, it’s time to move forward.”

Sullivan’s material is mostly original comment and I imagine that there would be some readers of his who would be willing to pay a regular subscription to access his thoughts – but he is surely among a tiny handful of bloggers that could charge. It is early days still in Blogland but already the market logic that led to the end of so many free services on the web is coming into play.

I wouldn’t expect many to turn commercial however. Those such as Instapundit, who provide rapid-fire links to breaking news stories as well as scouring the web for interesting comment/features, get a huge amount of hits but rely so much on other people’s material that they would surely come across legal problems in going pay-per-blog.

What the Sullivan statement does reveal for sure is that all those ads for Amazon books and the donation jars, probably aren’t making the bloggers as much money as some may have imagined.

Which reminds me – I better get back to work.