There's a trend for books to be written exactly like that, using material from blogs like Random Acts of Reality and The Old New Thing. This can lead to a strange effect when an opinion shifts half-way through the book. For instance, Joel on Software has a few chapters which refer to .NET. In chapter 43 (written on 22nd July 2000) he says "I'm not saying that there's nothing new in .NET. I'm saying that there's nothing there at all." Then in chapter 44 (written on 11th April 2002) he says "Why bother moving to .NET at all? Simply put, it's because .NET appears so far to be one of the most brilliant and productive development environments ever created." It's reasonable for him to change his mind over a 2 year period, particularly once a new product has actually been released, but it's quite jarring when the same shift happens within 8 pages. So, I agree with Petzold that it would be better to use the original blog posts as a starting point, then weave them into a cohesive structure.
Still, it can be interesting to look back at old blog posts: I sometimes do this when I meet a new friend, and want to find out a bit more about them. This leads onto Pliny, or Gaius Plinius Secundus to give him his full name. He lived in ancient Rome, and wrote various letters to friends and colleagues which were then published. Several of these letters were on the GCSE Latin syllabus, so we studied them in class and then had to translate them in the exam. This was in 1990, and it seemed a bit weird to be reading someone else's letters, but the teacher said that it was the equivalent of someone writing a letter to a newspaper. Nowadays, a better example would be a blog, and the letters do provide an interesting historical record. So, I recently decided to read through the Penguin book, i.e. the English translation of all his letters.
Overall, I'd say that it's a good book, and Pliny comes across as a smart guy. I don't agree with all his views (e.g. he would have had me tortured and/or executed as a Christian), but he had a strong moral code, and did his best to make the world a better place.
Pliny clearly didn't have a problem with the concept of slavery, since he kept several slaves himself. However, he seems to have been fairly benevolent towards them, and was willing to grant them freedom on several occasions. For instance, in IV:10 (book 4, letter 10), he inherits a slave, and it was clear that his friend wanted the slave to be set free on her death, but she didn't actually write that in her will properly. Pliny's solution was to say that even though legally she hadn't freed the slave, he'd do it on her behalf (as the new owner), since he viewed it as his moral responsibility to carry out her wishes. It's important to note that slavery in Rome wasn't really a racial issue; certainly not to the extent that it was in the USA.
I visited Italy on a school trip when I was 16: we stayed in Sorrento (Bay of Naples), and used that as a base to explore the surrounding area. In particular, we went to the ruins of Pompeii, and climbed Mount Vesuvius. Pliny was present at the eruption which destroyed the town, and his first-hand account is a valuable resource.
The main thing that struck me about the book is how little has changed in the last 2000 years; our technology has come a long way, but human nature is much the same. For instance, in IX:6, he makes it clear that he's not a fan of chariot races:
The Races were on, a type of spectacle which has never had the slightest attraction for me. I can find nothing new or different in them: once seen is enough, so it surprises me all the more that so many thousands of adult men should have such a childish passion for watching galloping horses and drivers standing in chariots, over and over again. If they were attracted by the speed of the horses or the drivers' skill one could account for it, but in fact it is the racing-colours they really support and care about, and if the colours were to be exchanged in mid-course during a race, they would transfer their favour and enthusiasm and rapidly desert the famous drivers and horses whose names they shout as they recognise them from afar.
I think that's a pretty fair description of football fans nowadays: they're loyal to a team, not to the individual players.
In II:14, he talks about people who are paid to applaud speakers: "If you happen to be passing the court and want to know about the speakers, there is no need to come on to the bench or pay attention to the proceedings; it is easy to guess - the man who raises most cheers is the worst speaker." I gather that much the same happens nowadays when people go to see The Jerry Springer Show, i.e. the audience are told when to cheer or clap.
On a more solemn note, Pliny mourns the death of a friend in letter I:12, and I think his words still apply to people nowadays: "Send me some words of comfort, but do not say that he was an old man and ill; I know this. What I need is something new and effective which I have never heard nor read about before, for everything I know comes naturally to my aid, but is powerless against grief like this."
He has some unusual views on secret ballots (by modern standards). Nowadays, the theory is that people need to be able to vote in secret, otherwise they can be coerced into voting for a particular candidate, and face violent reprisals if they don't go along with it. However, Pliny had doubts about the wisdom of this new scheme. In III:20 he said: "I am afraid that as time goes on the remedy will breed its own abuses, with the risk of wanton irresponsibility finding a way in. Very few people are as scrupulously honest in secret as in public, and many are influenced by public opinion but scarcely anyone by conscience." Later on, in IV:25, some of his concerns turned out to be justified: "At the recent election some of the voting papers were found to have jokes and obscenities scribbled on them, and on one the names of the candidates were replaced by those of their sponsors." I haven't seen the voting slips from any UK elections, so I don't know whether the same thing happens now. However, look at YouTube, where people can post anonymous comments without being held accountible. Does this lead to valuable insights, or things that make you despair of humanity? (I'm with xkcd on this one.)
On a more cheerful topic, I was amused by I:4, where he writes to his mother-in-law: "What luxuries you have in your houses at Ocriculum, Narnia, Carsulae, and Perusia - even baths at Narnia!" This was a town near Rome, although sadly it's since been renamed to Narni, so you can't quite go to Narnia on holiday.
One slight problem with the book is that I'm not familiar with all of his "pop culture references". For instance, in letter III:9 he says: "We also had in mind the well-known example of Sertorius, when he set the strongest and the weakest of his soldiers to pull off the horse's tail - you know the rest of the story - and concluded that we too could deal with the large number of defendants if we took them one by one." Cornelius Minicianus may well have been familiar with this well-known story, but I'm not! There's a footnote which refers me to Horace, Epistles, II, I, 45-, but that doesn't shed much light on things; call me lazy, but I'm reluctant to read another book just to understand the footnotes in this one. Fortunately, I've found an online copy; it's still a bit vague, but I'm inferring that the strongest soldier grabbed the tail in his fist and tugged on it unsuccessfully, while the weakest soldier plucked the hairs out one at a time. (I'm not sure how either of them avoided getting kicked in the head by the infuriated horse.)
In the final chapter, Pliny has been sent out to one of the provinces as a local governor, so all of his letters are addressed to Emperor Trajan. The significant thing about this chapter is that we also have a copy of Trajan's replies, which doesn't happen for any of Pliny's other correspondents. In a way, this reminded me of Bujold's novels, where people are sent out with the full authority of the Emperor to a remote location so that they can act on his behalf. In X:33, Pliny asks for permission to form a group of firemen (consisting of about 150 men), but Trajan refuses for fear of revolt (in X:34): "If people assemble for a common purpose, whatever name we give them and for whatever reason, they soon turn into a political club."
That may seem a little harsh, but Trajan later steps in to squelch one of Pliny's bad ideas. In X:54 Pliny is struggling to find a use for public funds, since there's nothing to invest in and nobody wants to take out loans. "Would you consider, Sir, whether you think that the rate of interest should be lowered to attract suitable borrowers, and, if they are still not forthcoming, whether the money might be loaned out amongst the town councillors upon their giving the State proper security? They may be unwilling to accept it, but it will be less of a burden to them if the rate of interest is reduced." In X:55, Trajan replies: "You can fix the rate yourself, according to the number of potential borrowers. But to force a loan on unwilling persons, who may perhaps have no means of making use of it themselves, is not in accordance with the justice of our times." Frankly, this is the thing I find hardest to accept about Pliny; I've never had to deal personally with torture or slavery, but forcing people into debt is just fundamentally wrong.
As I say, though, overall I liked the book, and I think it's worth reading; even when I disagree with him, he makes his points eloquently.