Mobile Friendly
Having a mobile friendly website is a big deal, to the point where it is at least as important - if not more important - to have a website that works well as well on mobile as it does on desktop.

As the penalties for not have a mobile friendly website can be harsh - from users abandoning early to depressed search engine rankings - all professional digital marketers are in complete agreement that a mobile friendly friendly website is table stakes.
Sitebulb's mobile friendly Hints are focused around issues that affect a webpage negatively when viewed on a mobile browser, and may cause the site to not be deemed mobile friendly.
Mobile Friendly Issues
All of the Mobile Friendly Hints are Issues, which means they represent errors or problems that need to be fixed. They are additionally classified in terms of their importance - this should be taken into account when prioritizing implementation work, along with the number and type of URLs affected.
Importance: High
These Hints are very important, and definitely warrant attention.
- Tap targets are too small or close
- Total page size too big for 3G connections
- Multiple viewport <meta> tags were found in the <head>
- Missing viewport <meta> tag in the <head>
- Font size is too small for mobile devices
- Content does not size correctly to viewport
- Has one or more image-map <map> tags
- Unsupported browser plugins found
Importance: Medium
These Hints are worth investigating further, and may warrant further attention depending on the type and quantity of URLs affected.
- The viewport <meta> tag does not have a width set
- The viewport <meta> tag has a specific width set
- The viewport <meta> tag is missing an initial-scale
- The viewport <meta> tag initial-scale is incorrect
- The viewport <meta> tag prevents the user from scaling
- The viewport <meta> tag has a maximum-scale set
- The viewport <meta> tag has a minimum-scale set