When you visit sites on the internet, your cache stores the files downloaded from these sites. If you return to the site later, you don't need to reload the same information.
If you clear your cache regularly, the sites will load faster and you will obtain the newest uploaded information. That's why clearing the cache of your browser can also improve your in-game experience - you will get all new features right after the game updates, and your game will run smoother and faster.

How do I clear my cache? You can find instructions how to clear the cache of the most used browsers.

Google Chrome:

Open Chrome on your computer
Click on the Menu Icon in the top right corner
Click More tools and then Clear browsing data ...

Then choose a time range. To delete everything, click All time.
Check the boxes next to "Cached images and files" and "Cookies and other site data".
Click Clear data.

Firefox:

Select the menu drop-down in the right upper hand corner and select Preferences.
Go to the Privacy & Security tab and click Clear Data under the Cookies and Site Data section.
Unselect the Cookies and Site Data option. Then click the Clear button.
Close the Preferences page.

Opera:

Launch Opera.
Click the Opera menu in the top left corner.
Click Clear browsing data in the top-right corner.
Select what you want to delete and the time range, like recent history or all time.
Click Clear data.

Safari:

To clear your history and cookies, go to Settings, choose Safari, and tap Clear History and Website Data.

To clear your cookies and keep your history, go to Settings, choose  Safari, then click on  Advanced.
Select Website Data, then tap Remove All Website Data.

Internet Explorer:

Open Internet Explorer.
Click the Tools menu in the upper right corner. Depending on your version of the browser, it will either be named "Tools" or will appear as an icon of a gear.
In the drop-down menu, choose "Internet options."
On the "General" tab, and in the "Browsing history" section, click the "Delete" button.
Make sure that "Temporary Internet Files and website files" and "Cookies and website data" are selected. Also consider clearing the checkbox for "Preserve Favorites website data."
Click Delete.