I am student in web programing. I use massively <table> ... </table> to structure my web page.My professor once told me it could decrease the referencing quality for my websites, so I ask myself this question : Why does a <table> tag is a bad practice in structuring a webpage instead of using it for basic data dysplaying ?
Using table tag to structure a web page decrease referencing quality?
googlebot;table
Using tables for website structure is an old practice, by some even considered even a bad one, with current technologies you got more options, maybe not ar intuitive as using tables but they come with great advantages. To list a few: Your code could be greatly reduced by using  wrappers instead of tables, which could result in smaller size websites and smaller loading times.Search engines find easier to crawl a website with less markup, so they can decipher between code and content.By using other structural techniques, you will be able to adapt easier to mobile responsive sites, or resizing your website for different screen sizes, which is a great practice in modern website programming.    Here there are some links 1 2 where you can see more advantages altho they could be quite old, I found them very useful. 