With each new board, the likelyhood of cross-posting or wrong-posting simply increases.
The current volume of traffic on the Tech board is manageable (and diverse). If there were sustained use for a particular sub-topic (like algorithms) which might deserve their own forum, then that could be decided when it needed to be decided.
If it isn't a language or platform specific question as covered by the existing forums, and it isn't random general discussion wibble, then the Tech board is the place for it to go.