When my European clients execute agreements, they routinely initial every page, usually at the bottom, in addition to signing at the signature blocks. Here in the U.S., I see that approach rarely; it is customary merely to sign at the signature blocks.
Several weeks ago I posted a LinkedIn question about this difference. [September 2013 update: Link to question no longer available because LinkedIn removed its Q&A feature.] Here are some of the insights that I gained from my colleagues: