Nokia

[CityFarmer]

This is still hindsight. Nokia can also choose to go Android+windows mobile model 2-3 years ago and they will probably be doing ok now.
There's nothing wrong with their hardware but windows mobile is simply a hype till date.

I do agree about the hindsight part, though my counter-argument would be that if you were investing in technology companies, then one should demand an even greater margin of safety as new technology moves so fast as to render old ones completely obsolete. History has shown this - an example would be the CD/DVD replacing casette tapes.

I agreed margin of safety is always necessary for investment, but may need a slightly different approach for technology stock

IMO, margin of safety solely on market price is flaw.
No amount of margin of safety in price is sufficient, if the choice is wrong. The price can go as low as zero
Any amount of margin of safety in price is too much, if the choice is right. You will always miss a gem.

Technology stock is always a special breed, and conventional wisdom might not applies fully

The concept of margin of safety on other fundamentals still relevant.

To share my 2 cts