I use Ubuntu as my normal OS, it allows me to not have to worry about viruses, and other Windows related problems. I keep Windows on my PCs, for the 1 or two applications I have to use for Windows.
Tether looks like a great product, but I would be a lot more interested in purchasing it if I could use it on the Linux side of my PC.
We are looking into the possibility of adding this functionality to Tether in the future.
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