SERPs modification by search engines

We've heards a lot about search enginestrackiig IPs and user behaviour etc. to modify search results. Bu not all SEO Company agree on this, some say dat results are shown from a data centre according to search engine algorithm hence is can't be modified, others say Search Engines reorder the results for revenue or maybe for user behaviour improvement.

But I personally think is search engines do tamper there results (as Shoaib Akhtar do BAll Tampering for getting more wickets). Recently Google also got a patent for changing top results. Thus no doubt search engine do vary there results.

Below are the 20 Ways Search Engines May Rerank Search Results :
1. Filtering of duplicate, or near duplicate, content
2. Removing multiple relevant pages from the same site
3. Based upon personal interests
4. Reranking based upon local inter-connectivity
5. Sorting for country specific results
6. Sorting for language specific results
7. Looking at population or audience segmentation information
8. Reranking based upon historical data
9. Reordering based upon topic familiarity
10. Changing orders based upon commercial intent
11. Reranking and removing results based upon mobile device friendliness
12. Reranking based upon accessibility
13. Reranking based upon editorial content
14. Reranking based upon additional terms (boosting) and comparing text similarity
15. Reordering based upon implicit feedback from user activities and click-throughs
16. Reranking based upon community endorsement
17. Reranking based upon information redundancy
18. Reranking based upon storylines
19. Reranking by looking at blogs, news, and web pages as infectious disease
20. Reranking based upon conceptually related information including time-based and use-based factors

Looking forward for Search Engine Optimisation Expert comments on this.........