i moved from Tallinn last year :) many positive things can be said about this place, but having a snow (mostly dirty) for about 7..8 months a year, and seeing this mess made me move:
http://public.fotki.com/dmitri_don/tallinn-2011/
I knew about the snow, but not about the derelict state of some of the surroundings. However, isn't it normal for a reasonably large city to have vandalized parts like that? I'm sure you could find similar scenes in cities like Paris, Brussels or Berlin.
If you have any other resources about Tallinn (biased or not ;-) ) I'd love to take a gander, it's actually quite hard to find good intel about it. I noticed you're Canadian - did you use a guidebook when you first arrived? I'm wondering which one I should get.
Best single Tallinn resource is probably In Your Pocket: http://www.inyourpocket.com/estonia/tallinn
You can pick this up cheaply in the city, download the pdf from their site for free, or get their iPhone app (also free).
Also new and interesting-looking is http://www.likealocalguide.com/tallinn
There is no great definitive online expat forum.
Also: when looking up stuff online, learn to love Chrome's built-in translation functions, and remember that it (and Google Translate) unfortunately does a better job with Russian than it does Estonian.
As for snow, 7-8 months is exaggerating, if not pure lying :) It's true, that the weather is not African, then again it is really varied and one of the few places where we do have 4 really distinct seasons.
At least the snow is white for most of this time (rather than dirty/sooty brown/grey as in many other cities), and it's less windy and humid than I'm used to in the winter (so it doesn't feel as cold as the thermometer says).