For a given random sequence ( C , T 1 , T 2 , … ) , the smoothing transform S maps the law of a real random variable X to the law of ∑ k ≥ 1 T k X k + C , where X 1 , X 2 , … are independent copies of X and also independent of ( C , T 1 , T 2 , … ) . This law is a fixed point of S if X = d ∑ k ≥ 1 T k X k + C holds true, where = d denotes equality in law. Under suitable conditions including E C = 0 , S possesses a unique fixed point within the class of centered distributions, called the canonical solution because it can be obtained as a certain martingale limit in an associated weighted branching model. The present work provides conditions on ( C , T 1 , T 2 , … ) such that the canonical solution exhibits right and/or left Poissonian tails and the abscissa of convergence of its moment generating function can be determined. As a particular application, the right tail behavior of the Quicksort distribution is found. [ABSTRACT FROM AUTHOR]