From BBCi:
"Tips for Using the Moleskine Notebook
Although the book will fit in a back trouser pocket, if you're going to carry it on your person, it's less damaging to the book to put it in your jacket pocket. (Although the book is light, placing it in a shirt pocket is not recommended.)
Always use the elastic to keep the pages closed. The pages may be acid-free, but they are not waterproof. Keeping the book closed tightly with the elastic will limit any rain damage to the page edges.
The ideal writing instrument for the standard size notebook will have a fine point (ie a maximum of 0.7mm). Either pen or pencil will work nicely.
If you're using the notebook as a creative writing aid, Bruce Chatwin recommended numbering each page for use as a reference guide.
Chatwin also suggested placing your mailing address in the inside cover, along with notice of a reward for recovery in the event the book gets lost. (The Modo and Modo version provides a space in the inside front cover for this information.)"
...
Burning sands, reticulated pythons, coffee grounds and crayons often take their toll on our little black books. What to do? Martha is busy taking notes from her courtroom seat so let's take the cudgels.
- I keep mine in Ziploc® when traveling.
[BBCi excerpt added 3.4.04]
Update 5.12.06
Alexia has a photoset on FLICKR about Moleskine repair.