Can I migrate content to non drupal sites I've been reading up on Drupal migration module recently and it seems like very powerful tool. That's why I was wondering is it possible to make migrations like Wordpress -&gt; Joomla with Drupal only as intermediary between those two.

I tried to find some answers to this question but so far I've found only X -> drupal migration
It's probably better to try to go directly from one system into another. Placing Drupal in the middle is likely to add complexity to your migration strategy. But hey, if you find that it solves some issues that your migrations face, then I see no reason why it can't be done.