There's a little ten minute film, here. But the gist... 11% of the mortgage market is buy-to-let, fewer than 1% of the 1.3m buy-to-let properties out there during the slump were repossessed, and - with first-time buyers suffering and older savers losing money in savings accounts - the popularity of buying properties to let is likely to continue.
Also, if I may, in the past you've asked why more people don't comment here. It might help if links opened in another window/tab, instead of taking us off-site completely.