Importance of Numbers in designing websites
Pictures are worth thousands words.
Same is true for numbers and formulas
When we are designing a website, showing screen shot/picture is much better than writing pages of text.
Same way many apect of website, software development are better represtened by numbers
If you are providing a personalized experience on website homepage based on male/female - you know there are two varaiation of home page.
If you are provding personalized experience based on Age (0-17, 18-25,26-40,41-60,61-80, 81 and more) - you know there are 6 variation of home page.
This helps you to determine - how much caching you need, how much variation you need to test. If you are gathering measurement on website usage, it help you bucket usage based on variation.
Take the above example further - You want to provide personalized experience based on Male, Female, Age factors, Profession and Income level. If you simply specify that you want to provide personalized experience it means at run time system will determine Sex, Age, Profession, Income Level. Based on various factors it will cretae home page showing relevant products. IF you get 1 million user a day , same set of queries will run 1 millions times a day.
If above information is represented in form of Numbers e.g
Sex : 2 possibilities
Age : 6 possible value
Income Level : 10 possible value
Profession : 5 possible vale
Overall you will have 2*6*10*5 = 600 possibilities. Instead of doing a compuation million time you can do 600 times and cache it. Instead of determining user info at run time, allocate user to 1 of these 600 bucket once. As soon as user visit , determine user bucket and show relevant page to user
The above is very simple optimization. More optimization can be done on top of these as Age group 0-10 will not have working profession or income and these buckets will always be empty. Overall number of buckets will reduce.