Just curious are there any chabadskers around here who ask the rebbe questions through the book?
And how exactly does it work
The Rebbe mentioned a few times after the passing of the previous Rebbe, that chasidim should continue writing to the Rebbe, placing it at the ohel, and those who are far away should put it between the pages of the Rebbe's Chassidus and the Rebbe will find how to answer.
That seems to be the source of what some consider a letter on the page of the Rebbe's letters, that they randomly insert their letter to, as an answer to their question.
Although I don't think that is what the Rebbe meant and I wouldn't do this myself, nor would I suggest it to others, I may even discourage it, for those who believe in it, it definitely works.
For this to make sense I'll ask if anyone recalls the story with Reb Mendel Futerfas who sent a letter במחשה from Soviet jail and his wife in London received a letter in response. As well as the gentleman in France who asked the Rebbe (in the 30s) whether he should emigrate to America and the Rebbe told him to write to the previous Rebbe who was in Russia /long story short/ he brought it to the post office who said they couldn't do anything with the letter as there was no mail between the 2 countries and the next morning the guy woke up with a certainty that going to America was the right thing.
PS. There was a famous story about a family in Australia who has a life saving miracle (I think the bit was in hospital dying from cancer) by acting on advice they found in a letter from the Rebbe that they randomly opened to (PM me for the name).
PPS. Whether you would use an encouraging word in a letter as a blessing or if you would actually make decisions with consequences base on it, well, that's each to their own.