maxBoost is described in the Spatial Pooler pseudocode [1]. As @alavin mentions at the end of his post, boosting is, by definition, only useful for really long and complex data sources where you need to optimally allocate the SP columns. For most simple streaming tasks it can be set to 1.0.
To my knowledge, swarming does not explore different values of boosting, just uses a default value of 2.0. I think that default should be set to 1.0. There is an existing NuPIC ticket [2] to improve the various swarm parameters, and this should be one of them. There are other parameters that could be improved in swarming.
[1] http://numenta.com/assets/pdf/biological-and-machine-intelligence/0.4/BaMI-Spatial-Pooler.pdf
[2] https://github.com/numenta/nupic/issues/2829