When Do Search Engine Rankings Become Useless?

Measuring success via search engine rankings isn't completely useless, but it's getting to be, and fast. There have been a number of times I've been on the phone with a client when they wanted to discuss their rankings. Of course, when we both perform the same searches on Google we'd get a different set of results. We've had similar things happen even from multiple computers in the same office. So what does this mean? It means that search engine rankings aren't what they used to be!

Bill Slawski had put together a great post covering the many ways in which search results may vary from person to person. Here's the list, but you'll have to jump on over to Bill's, SEO by the SEA blog to get the explanations:

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