I have a lot of experience helping self-published authors promote and sell their books, so I hope I can help any of you who are thinking of turning your blogs into books. The most important thing you need to be aware of is that once you've produced your book, if you're going to sell any copies, you need to promote it. There are 6 million (!) books on Amazon UK so there's a lot of competition out there...
I've just written a book about book promotion called "Sell Your Books!" - you'll find it on Amazon if you search for that title and my name, Debbie Young. (Hope it's not breaking Mumsnet rules to mention it here - just trying to show I know what I'm talking about!)
There are lots of companies who can help you self-publish (I can recommend SilverWood Books, who commissioned my book to help their authors) or you can learn to do it entirely yourself. There are all sorts of considerations to take into account before you decide how to do it, not least cost!
However you do it, shout about your book once you've published it! Promotion needn't cost you anything - blogging about it, for example, is a great, free way to raise your book's profile - Madame Guillotine is a prime example of that! My book gives lots of other helpful suggestions too. (And Mumsnet gets a mention too!)
By the way, I'm now planning to turn my YoungByName blog into a book, one year's worth of posts at a time, and you can bet I will be promoting it like mad!
Happy to help with any further questions if anyone wants to ask me!