Are tags portable, and if so how? I am a relatively new Mac user, recently bought a MacBook Pro with OS X 10.9.1. 

I see that there are tagging capabilities within the file system. I'm concerned about portability. If I get a new computer in a few years, how would I transfer my tags to the new system? What if I want to move my files to a Windows or Linux machine? Can I see the tags on these operating systems? 

I just don't want to put some effort into the built-in tagging system only to have my tags useless at some point down the road.
Tags are not 100% portable in that they don't always survive mailing or copying to other computers such as Linux or Windows. On that respect, it's more about those OS supporting the Apple filesystem. I am impressed that even copying tagged files to a SMB formatted USB drive preserves the tag metadata and most copy operations from and to another Mac via an HFS+ hard drive or share does preserve the tags well in practice. (Even copying the file to a 10.8 or older Mac didn't strip tags in my tests).

Apple's article covering tags, http://support.apple.com/kb/HT5839, recommends:


  If you want to include your Tags when sending files through Mail, Messages, or other apps, compress your files and folders before sending them.