Creating an account is free and easy. It also has several other advantages over editing logged-out.
Anonymity under your chosen user name
Although those editing logged-out are often called "anons" on wikis, they are actually identified by IP number. This is publicly visible in the "history" page and recent changes each time they edit. For many people (for example those using AOL or other large Internet service providers) this doesn't give any information to others. But in some cases, for example if you are editing from a work computer, this may allow others to work out your location or other details. If you are worried about this, you should log in to edit. Your IP address will then not be visible to other contributors.
A way of joining the community
Becoming known under a user name means that you will be able to gain reputation and recognition in the community. It's difficult to remember whether or not you have met 220.127.116.11 before! You can also make a personal user page once you are logged in. The link to your user page will appear at the top right of the screen. You will also have a personal talk page, and will be notified with a banner each time someone adds a message. Being able to communicate easily makes it a lot easier to build a wiki.
Being logged in allows you to rename pages (with the "move" tab) and to upload images. You can also easily view your contributions using the "my contributions" link at the top of the screen, and make a personal watchlist to keep an eye on your favourite articles.
A lot of the look of the site can be changed with customisation. Using the "preferences" link, you can change the overall look of the site, your time-zone preferences, search settings, and much more. If you know CSS, then you can change the look of the site even further with your personal style sheet.
So please consider creating an account and logging in. It's free, and very easy. Click here to go to the log-in page.