Yes Donald, they do affect the @@rowcount variable. Say for example you have the following trigger on Table1 then you would only receive those Rowcount which may be result of the DMLs written in trigger itself.

Create trigger abcIns

on Table1

for insert

as

      declare @col1var int

      insert into #temptbl(timeofinsert,idoninsert) values(getdate(), @col1)

return.

Now whenever any insert is made on Table1 it will return only the rowcount of the insert statement(it may be any DML statement) inside the trigger. This carried to scope of the session in which trigger firing insert statement was issued.