Hey italicus,
Nice to see you again
I haven't done any research on these... I did try to install the Google Desktop Search but it didn't like my Antivirus...
Are they safe? I would say so however it would all depened on who and where you download it from. I'm sure Google and any other popular search engines wouldn't be stupid enough to add spyware into it but you never know.
Tell your friend that he/she should only download Desktop Searches from popular search engines such as Google.
To be on the safe side your friend should download some
spyware removal tools (Your friend will need to make sure he/she downloads the updates) to make sure that there are no leaks.
Other then that I think your friend should be OK.
Let me know if there are any problems
Tech