I find it amusing that there are technically 3 "thanksgiving" holidays.
The first of the three is Mabon - or the Autumn Equinox, or second harvest - which falls some time around September 21st to 23rd (so is commonly celebrated on September 22nd). This is the thanksgiving for many Pagans.
The second is Canada's thanksgiving, which falls on the second Monday of October... Today!
And the third is America's thanksgiving, which falls on the fourth Thursday of November.
There may even be more of them for all I know, but these are the three I know exist.
Each of the different cultures - and each different family, group of friends, etc - celebrates differently, and (like with all holidays) some groups make a big deal about pointing out the differences; making out that their thanksgiving - or their way of celebrating thanksgiving - is the "right" one, and everyone else is doing it wrong. Let's focus instead on the similarities between them; I think it will be a nice change!
Stop for a moment and think... What's thanksgiving all about? Regardless of which of the thanksgiving type of holidays you celebrate, I'm sure you'll come to the same answer - in some shape or form - as everyone else.
Thanksgiving is a time to be with family and friends, and to give thanks for everything in your life you have to be thankful for; a good harvest (or a well-stocked local food supply... Even if it's a local supermarket), the clothes on your back (even if it's the only set you have), the roof over your head (in theory), your friends and family, etc. So, during this thanksgiving season - whether you've already celebrated your thanksgiving, are celebrating it today, or have yet to celebrate it), remember to be thankful for those things. But remember the most important thing... You should be thankful all year round, not juston thanksgiving!
Anyway, to wrap up this post, I just want to say one final thing:
Happy Thanksgiving to Canada, and anyone not in Canada who chooses to celebrate their Thanksgiving on the second Monday of each October along with Canada.