The Register has interesting article on 50 people that were arrested in Romania for using smart phone spying tools to spy on their spouses, competitors, and other people who fell victim for one or another motivation.
We have covered there spying tools already in 2006, back then the first versions of these tools were classified as trojans, later variants are classified as riskware. And while they have not made much into news lately they are actively used as we can see from this Romanian case.
These spying tools are just another manifestation of age old problem, when someone wants to pry on other person's private matters, they will use whatever tool they have access to. Jealous husbands and suspicious wives have been installing keyloggers and other monitoring tools on their spouse's PCs for at least 15 years now. And now as phone spying tools are readily available they will be used to victimize phones, just another tool in a spy's toolkit.
Which means that if you have reason to be concerned about your privacy, it might be a very good idea to keep good care of your phone, and maybe install some protection.
The good news about these mobile spying tools is that they cannot be installed remotely to a device, in order for someone to spy on their victim they have to be able to access the phone and install software to it. So the simple and efficient protection against these tools is to set up lock code on your phone, when the phone is locked nobody can surreptitiously install unwanted software.