These letters are easy enough to spot. 

But some spam is genuinely hard to distinguish from real.

For instance, right now, as I was reading this thread, this box popped
up all on its own, asking me if I want a software update that improves
the security of the software update process. 

This is probably genuine, but it looks and feels like spam, if only because
it's exactly the sort of thing that John Cleese and Eric Idle, the founders
of the spam metaphor, might have written!

If I answer it, will I get another popup that asks me to improve the
security of the improvement in security of the security-improved
updating of the updated secureness of the update?

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