Your user profile and avatar are your own little prime space. They appear at the end of each of your posts and serve as a marker of your own personality.
Adding your avatar and profile are optional, but it adds a personal flair to an otherwise plain page. Furthermore, that image of you (or representation of you, if you are camera shy) appears on the home page and categories as markers for your posts.
Adding an Avatar
Whyrll uses Gravatar, a globally used avatar system. If you already registered to Gravatar.com using the same email you used when registering to Whyrll.com, then there is no need to re-upload one.
Otherwise, go to Gravatar.com, sign up for a WordPress.com account, verify and then authorize Gravatar. You will then be redirected to your Gravatar dash where you can upload an existing image, take a photo of yourself via webcam (smile) or use an image from the internet. Crop and finalize. Your newly uploaded Gravatar will automagically be used by Whyrll!
Adding a Profile
Now for your profile. You can add that by clicking Profile on the left of the Whyrll dash and filling up the biographical info which you will find if you scroll down a little down. Be concise, but add lots of personality. Remember, it is your mark!