I know stories of some people using this rune - invoking this rune - and this is something you should never do lightly. Isa is a powerful rune. Its simplicity is the key here. A single straight stave, the icicle, the individual, being alone, the 'I'. Invoking this rune can leave those who invoke it feeling paranoid as friends and family desert them.
To invoke Isa is to invoke isolation. And this seems to be the very root of the rune. We connect the rune with Ice and the rune poems tell of its icy properties. But this is just a poetic translation, for the harsh winters of the North would have left the families and communities isolated.
Isolated is rooted in 'Isa' and we can see an example in the old French word isolé (Isolate). The word has evolved and used in English in the words isle and island, The name 'Iceland' is probably the best example of how the name invokes both meanings of the root - Icy and Isolated!