My students are obsessed with the Diary of a Wimpy Kid series. At no less than 5 requests every single day, these items are hot commodities in my school library. At the end of the year I was finally able to wrangle the first installment to see for myself just what all the fuss is about.
The very first observation I had about this book was that Greg Heffley is a little jerk. He's narcissistic, rude to his parents, completely self-absorbed, and the most inconsiderate, selfish "friend" any kid could ever have. But, you know what? A lot of upper elementary/middle school boys are just like Greg Heffley. I suppose at the end of the say, it's all a part of their emotional development and that they are who they are at this stage for a reason. Still. He might be funny, but he's still a little tool.
And he is most definitely funny. Greg Heffley makes some pretty witty observations about the social order in schools that I think most educators and maybe even parents miss out on. There is a tinge of a "bully or be bullied" theme which I definitely believe is part of the under-the-table social interactions between students. Another observation I have is that the books are 5th grade level readers, which I think is overestimating a bit. These books are not exactly solid 5th grade level material. There are illustrative comics interspersed throughout, which make it even more popular with kids. These kiddos do love their graphic novels (sigh)...
Overall, it's a good set to have in the school library. As for me, I'm done with you, Greg Heffley. But I like that my kids like you, so maybe you were worth my time after all.