caniuse.com
Caniuse.com is a site for developers with an index of support for different code. Here you can search different properties, values, queries, and more to see what browser support you have for them. There are suggestions on the homepage as well as a search bar that allow you to check support for the code you are looking to use. They have an index that shows you a ton of CSS, HTML5, JS, and other codes and their compatibility.
Uses
There are many ways to utilize the information on caniuse.com. For one, you can use the search function to see if a specific property you are using will show across all major browsers. This will allow you to change your code as needed for maximum user support. You can also browse through their index to get ideas for code. The index has links to plenty of properties, attributes, etc. that may inspire you to design differently. There is a link in the header menu to news where you can stay up to date on new features that have been released or gained support. This is a great way to stay current in your development. There is also a link in the menu for comparing browsers. This allows you to select multiple browser versions and do a side-by-side comparison of their support through the entire index.
Properties
One property that intrigued me was the background-attachment property as I have never utilized this myself. I have seen several sites that have utilized this property to have and image stay fixed while the content continues to scroll. I think this is a nice way to have a section stand out from other sites.
Another property I chose to review is text-indent as it is one I use frequently. Given that I only set the value, I have excellent support for this property and I find it to be a great way to style paragraphs to be more user-friendly and familiar as it mimics how we typically see text written.
Summary
Can I Use is an extremely helpful site for developers. They also do a great job at ensuring accessibility with a feature to change the support legend colors for color-blind usage. This is a great site to utilize to ensure maximum user support as well as to stay up to date on new features.