QUOTE(TreasaSalyer @ Nov 24 2013, 07:12 PM)
You are right, when you do link building or directory submission, you get result at that time but when there is any update your ranking goes down so you have to be careful to it I will say.
But I think without these techniques, We can not able to improve our site position in Google. You are also right that after any new update, ranking goes down But only because of that we say that the result of SEO is unstable and we have do SEO for any website till the lifetime of the website.