I am developing a Bitcoin application, so I am sending a lot of "toy" transactions for testing, with 0 fees.
But it seems that those take forever to get confirmed. (Right now I am waiting 45 minutes for one transaction to get confirmed. Previously it was about 30 minutes.)
Is my suspicion right, or am I doing something wrong? How important is the fee for miners? Do they preferentiate?
Or am I doing something wrong (not broadcasting to enough nodes, maybe?)?
And do nodes, that aren't miners (with official client I presume), preferentiate to send around transactions with fees?
(edit: note that the question was written in 2012, when the blocks were still empty.)