One of the best productivity tools I had when I used Microsoft Windows was a collection of portable applications. I missed those tools when I migrated to Linux. Now several open source projects could make portable apps available to mainstream Linux users. Three websites are trying to create that functionality. But the efforts might need more work before they all perform well out of the box. I found that being able to get these portable apps to run is largely hit and miss. Sadly, my testing showed that it is mostly miss.