For me, this site is a must-bookmark site! I hate running across a file extension and not knowing what it means or what program it is associated with. With Dot.What? you can get rid of the guess work and look up your file extension in their database!
Have a file extension you’re trying to figure out? Just type it into the search engine at the top of the page and click the button with the > on it to search for what it is. You don’t need to put in the proceeding dot when you search for a file extension. For example if you were looking up .wav, you would only type in wav to search.
You can also use the alphabetical navigation at the top, or the category menu on the left side of the page to navigate the site.
If you just want to learn about different extensions, I suggest clicking into the categories that interest you (for me that was fonts).
If you scroll down the main page, you can see what file extensions were recently added, commented on, updated, or viewed.
This is an awesome resource! Check it out today!