Yod-dropping refers to the dropping of the palatal glide in English. In British English, most speakers pronounce the palatal glide following coronals and most American English speakers do not. As a result, for most Americans the words "do" and "dew" sound the same but for most Brits they do not. Canadian English also exhibits yod-dropping but it is not uniform in all speakers.
Examples of words which are usually pronounced with a palatal glide in British English are "tune," "duke" and "student." In Canadian and American English, the palatal glide is usually not pronounced in these words. In fact, in an experiment conducted in southern Ontario, approximately 80% of speakers exhibited yod-dropping in words with coronals.
In my accent, yod-dropping varies. I drop the palatal glide after a syllable-initial -st. I do not pronounce it in words such as "student" and "studio." I do not pronounce it in "tutor," "tumour" or "tune." However, I do pronounce the palatal glide in "Tuesday." Also interesting is that I pronounce the palatal glide in "duty" and "dew" but not in "dune" or "duke." I am also inconsistent with respect to the alveolar nasal. I pronounce the palatal glide in "new" and "neutral" but not in "neuter." My pronunciation seems to reflect a mixture of British and American English.
Yod-dropping is common in Canadian English. It shares this in common with American English. However, it is not uniform among speakers of Canadian English. My own pronunciation attests to this. This may be another indication that Canadian English often combines features of two other English dialects, British and American.