Sometimes you just needs items that have been updated in a certain period of time.
You can do this with a CamlQuery, in this example I’m looking for items that have been modified in the last 80 minutes;
Basically you generate a DateTime object and format it to the right format.
Also look at the ‘IncludeTimeValue’ option of the query…
<View Scope='RecursiveAll'><Query><Where><Gt><FieldRef Name='Modified'/> <Value IncludeTimeValue='TRUE' Type='DateTime'>" + datetime + "</Value></Gt></Where>><OrderBy><FieldRef Name='Modified' Ascending = 'true' /></OrderBy></Query></View>