Site rank decreased in search resluts SERPs

Once you had a site hitting top search results?
Now it is falling in SERPs?
search your fault among the following :

1- Pop-up advertising, after your site come up, you may find pop-up advertising effective in generating revenue, but it may cost a lot.
2- Copied content , no genuine content.
3- Errors in sitemap, very common.
4- Your site might be hacked?
5- your site is slow, many images or high code/text ratio.
6- links for you are removed from sites linking to you.
7- bad content : serials, cracks, music, movies downloads ... all goes down.

Google changes Search results "SERPs" continuously

Many webmasters can observe obvious changes in search engine ranking positions specially at Google.
That is why fellows at are building a new thread every month to dicuss these changes, but are these really new factors driven to detect better results? or just changes in the websites?
Google said that positions depend on hundred of factors and new factors are added continuously, these updates can be followed on their webmaster Blog or twitter.

May be it is the main rule of universe : "change".

whatever done google will always be a machine and bad links may come up on first results, change is a must.

how to cope with this change?
currently google is focusing on website speed, it is necessary to make most of content in least space possible in kbs, this is good for SEO and for visitors, bounce rate and avg time on website.

Never think that your site made it to top search results, Google will never be a friend to a website while better one is out there, your site hitting top search results does not mean it can not be penalized or "sandboxed", google said there is no such thing.

I personally saw websites falling down after hiting the top at SERPs, main causes and faults are :
1- bad advertising : POP- Ups
2- Heavy pages
3- Keyword stuffing
4- Content : copyrighted content or hack related even if only a part of website.
5- selling links.

you must follow changes by google, try to make your website clean and fast, that's it.

Backlinks may harm !

It is not always good to have back links from lot of sites :
1- if so many in short time it is considered spam
2- if many in long time not related to site activity and users, it is considered paid SEO
3- if from directory, mostly useless
4- if from unrelated site, totally useless

it is important to make the back links increase by flow, let your users give you back links.
if you are a blogger add social bookmarking gadgets, or give the link of the post or page in an html code area, as youtube for example...