Over the years the PC Gamers and their demands have changed the LCD markets. Manufacturers of flat panel screens have prioritized speed over color accuracy by reducing the 8-bit RGB color representation (24-bit total) down to 6-bit (18-bit total). This newer technology produces much faster & brighter displays on laptops or desktops and due to popularity it has sold in high numbers.
With this additional display type among the PC users, now it has become even more challenging for photographers to present their work accurately on the web.
What is the difference? 262 thousand vs. 16.8 Million colors - a whopping 98% of the colors missing! The 6-bit systems exaggerate the overall brightness levels to produce extremely bright whites and very deep blacks - pushing the colors into much deeper hues (good for web graphics, videos or games). But in comparison, softer colors like yellow are especially not as strong, having a negative effect on skin tones. Below is an example of a photo optimized for each system to show the difference:
The human eye can be fooled to a large degree but, photographs definitely do appear brighter and more blueish with cooler colors (almost a fluorescent effect). The picture on the left would appear too dark & yellow on 8-bit systems and the one on the right would appear too bright & washed-out on 6-bit systems.
In digital photography the Computer is the only dark room to process the raw images from the camera and the human eyeball in front of its "display" is the final judge in making corrections. Photos corrected to look good in one system, would become out of balance when viewed in other systems.
There are a lot less issues with a printed photograph because it has no light source of its own and the human eye automatically makes a lot of the necessary adjustments for the ambient lighting. Invariable viewing-experience of photographs on the PCs will remain an issue, until the day we all use a consistent display system.