Google has stated it's Chrome browser, one of the most popular, will start giving warning messages when the page contains "mixed content" that is content being served from both secure and non secure sources.
What does this mean? Well firstly most viewers when confronted with this message will likely just move on somewhere else, a potentially lost client.
What needs to be done? You need to ensure every page on your site is only serving secure content, this includes images, banners from links (when will the escort industry ditch this 1990's spammy system?) and any internal links where the full site address is being used are updated to https or removed.
Going forward just make sure if you are adding your own link banners they do not contain images served via http. If you rely on someone else make sure you make them aware of this. The only other real issue is potentially linking to external images in blogs, so again keep an eye out.
Where Chrome goes others are likely to follow so we believe this will apply across all browsers in short order.
Of course as always if you need any advice or more information please let us know. We are here to help!