'most' of the delivery issues are with US deliveries - sending and receiving. I reckon it's the over-zealousness of the U.S. Govt having to check every parcel for BOMBS - OOPS, don't mention that word...........
Gav, your problem was probably related to the postal strike in Canada???
Mike - this was a "real" issue at the start of this year. A friend of mine works in Customs and told me that there was a "security" issue in the US that forced more thorough inspection on imports. More time was spend processing imports than exports, so there were delays.
On a side note - for those that think that insured or registered mail is quicker that regular mail from Australia to the USA - think again. A "regular" international post letter takes around 7-10 working days, and a "Registered" and "insured" envelope can take up to 5 weeks ! Aussie Post won't tell you that before you send.