If I view one of my user created pages using Chrome, all formatting is lost. If I view the same page using Safari or Firefox, I am able to see bold text and paragraph separations. Has SmugMug been tested and certified for all prevalent browsers and is there an ongoing effort to keep abreast of browsing technology?
As outlined in the SmugMug | Supported systems page, the following is fully supported:
Generally speaking, the above only applies to the built in styles and themes. If you customize your site, you can absolutely break things and cause the styles to become significantly different in different browsers.
Many CSS items are not supported the same way across major browsers, because many of them do not implement the same standards or to the same extent as others. In many cases you will find that you have to implement a type of "hack" to get it display correctly in a certain version of a popular browser(I'm looking at you IE7).
One caveat is if you have something like the "New Gallery Style" enabled from the SmugMug Darkroom. If this is enabled, you will see a different style then your users, as well as in any browsers that you have not activated it on.
If you have a specific item that is displaying differently in multiple browsers, I would suggest opening up a new question and specifying exactly what element you are having the issue with, and in exactly what browsers and versions. From that we would likely need to dive into your code and see what the best workaround might be!