While usability tips are applicable anytime, they are generally intended for Flash interfaces that work like regular software applications or interactive movies in which the user needs to be in control. However, Flash is used for a wide range of other purposes as well.
In high-concept interactive art pieces, such as requiemforadream.com, the concept of usability is really rather moot. The goal of the work is that users should be disoriented and should have to struggle through, interpreting things as they go. In such cases, the quality of the experience outweighs any traditional concerns about interfaces looking or acting a certain way.
On the other end of the spectrum, a Flash shopping catalog would certainly not benefit from the artsy, experiential treatment. High-visibility, functional interfaces are the way to go whenever a specific task is at hand.
The point is, take all discussions of Flash usability with a grain of salt, and judge for yourself the fine line between software and interactive art.
Think Like a User
Web browsing is a harried activity. The Internet is the ultimate in convenience, the first fully automated, instant distribution system for digital media. Web-site users are accustomed to moving quickly, grabbing a few paragraphs here or there, and then following the first link that looks interesting. They're on a mission.
Why, then, do most Flash sites take a long time to load and require so much effort to get around in? Simple. The designer wasn't thinking like a user.
"These buttons are so small!"—Fitts' Law is one of the keys to better usability. Put simply, the smaller a button is and the farther away it is, the longer it will take for users to home in and point to it with the cursor. Tiny (or moving) buttons, although trendy, can take several seconds to acquire with a mouse, adding up to a lot of user errors and frustration. Do yourself a favor and make clickable areas bigger and squarer, arranged in logical groups.
"I'm looking for something."—How easy is it for your visitors to find what they're looking for? Having clear and persistent navigation helps, but searching is also a must for sites of more than about 20 pages. The free service Atomz Search can provide indexing and searching for Flash sites. Atomz can read HTML, SWF, and even PDF. Did I mention it's free?
"This is taking too long."—Don't turn your home on the Web into another "Skip Intro" site. Drop the splash page animation—it's so 1998! If you really want to showcase your mad skills, create a special section on your site for animation demos. Other ways to trim file sizes include breaking movies up into several smaller pieces and making soundtracks an optional extra.
"I want to bookmark this."—Can users bookmark sections of your site and know that they'll be coming back to the same place later? Designers of highly usable sites do everything they can to ensure that bookmarks never break, even after an overhaul. If folks are keen to come back, don't disappoint them.
"I want to leave."—Never, ever make it difficult for users to leave your site. Exit pop-ups and other awful tricks just say "net porn" and will leave a poor impression. At all times, visitors should have access to the address bar or the Back button to make moving on a breeze.
It might sound obvious, but Flash movies on the Web are viewed using a browser designed primarily for rendering text. It pays to be a good house guest, and that means doing the best you can to not disrupt the habits of browsing, such as Back/Forward navigation and bookmarking. Here are some tips for being browser-friendly:
Preserve standard navigation—A popular Flash site style is the "CD-ROM," in which a pop-up window launches with no navigation or address bar. The aim is to pretend the user isn't on the Web but is using the site like it's a separate program. Instead of hitting the Back button to leave, users must switch gears and look for the Close button instead.
Play favorites—Favorites and bookmarks are one of the biggest generators of Web traffic around. However, many Flash sites aren't designed to take advantage of this feature and, in fact, ignore it altogether.
Avoid window abuse—Popping up windows with custom sizes may seem like a good idea, but it's actually a cause of inconvenience for anyone who doesn't always do full-screen browsing. Macintosh users especially are affected because the next new window that they open will conform to the size of your pop-up, forcing them to resize it by hand.
Don't be afraid to scroll—So many Flash sites that I visit forget that they needn't design movies like standalone software, sized to 100% x 100% of the browser window. Flash movies look just as good (or better!) in page form factors that users scroll like regular HTML. Providing Flash content in a page format is good from a bookmarking perspective, and it also preserves the "click or scroll" habits of browsing.
This is bad practice for so many reasons, but the biggest is the break in navigational consistency. If Flash sites are to be usable, they need to conform to Web standards. So, if you absolutely must launch a new window to display some content, leave the navigation, address, and status bars intact.
Putting your whole site into one big movie may eliminate the pauses or load breaks between pages, but it raises the bigger specter of useless bookmarks and broken navigation.
To fulfill users' expectations and make your site more browser-friendly, break Flash content into logical page-sized chunks, and link between those pages. To avoid unnecessary downloading of symbols that exist across multiple pages, use the handy Shared Library and Linkage features provided by Flash.
If you must open a new window to display Flash content, avoid specifying a size; your users will appreciate it!
Keep It Visible
Visibility is an extremely powerful principle, derived from the old maxim "out of sight, out of mind." Literally, if users can't see something (either on the screen or in their mind's eye), then it doesn't really exist for them. And when something important isn't visible, the user will suffer along without it, give up in frustration, or just make errors. Here are some tips to keep in mind:
It's important to understand that seeing and looking are not the same thing. You can look at a page of French literature, but unless you know the language, you don't see much at all. Seeing is a form of associative memory recall, where symbols and images trigger us to remember previously learned information. This is why it's vital to follow Web conventions; users are rarely willing to invest too much time in learning your unique visual language. Imagine having to learn a new language every time you pick up a book!
Keep navigation simple—Don't hide information to save space. Navigational elements need more than just icons; they also need descriptive labels and even explanatory text. Icons that might make sense to you will probably just appear cryptic (or not even look like buttons) to users. Remember, the primary mode of navigation on the Web is the text link.
"What's taking so long?"—Computer users are easily fooled by pauses. Anything in your interface that doesn't respond immediately will prompt a response like "something's wrong." But, as we all know, transferring files across the network can take time. Provide feedback in the form of a loading animation or progress bar whenever an operation will take longer than a second or two. Anything over 15 seconds should be accompanied with a timer so that the user knows that the wait time is normal.
Respecting the single point of focus—Flash is a powerful animation tool, so some restraint is useful during the design process. Keep in mind that humans can look at only one small area at a time, so a screen full of simultaneous action will end up a distraction.
Controls and cookies—Any user decisions that result in cookie settings (such as "Log Me In Automatically") should be undoable at a later date. Try adding a section to your site dedicated to changing user preferences, if you offer any. Other controls, such as audio on/off switches, should be visible and available at all times.
"Where will this lead?"—Program Flash links to be better than their HTML counterparts. Include floating "tooltip"–style labels that describe where links lead to, and, wherever possible, inform users if a link will spawn a new window. The default browsing expectation is that links will open a new page in the same window, not a new one. Also use short-term cookies to remember which Flash links a user has already followed so that they can appear in a different (usually brighter) color.
Like visibility, readability isn't as simple as you might expect. It's a combination or using great fonts (at reasonable sizes), high-contrast layouts, and, most importantly of all, good written expression. Take a look at these tips for readability:
Get a copywriter—Flash is great for graphics, and it does a fair job with text, too. But the words themselves are something that software can't help with. Paying attention to important issues such as grammar, spelling, tense, and tone is vital if you want to communicate clearly.
Select the right font—Typography is both an art and a science, and one of the cornerstones of good type is selecting appropriate fonts. Conventional wisdom dictates that sans-serif fonts, such as Arial and Helvetica, are best used for headings. Serif fonts, such as Times and New York, are better for body text where easy reading is important.
Use sane font sizes—Teeny tiny writing, especially in navigation but also in paragraph text, is bad news. Many people have less-than-perfect eyesight, and Flash content can now be viewed on TV set-top boxes and handhelds. To test the sanity of your font size, try sitting 4 or 5 feet away from the monitor, and see if the text is still easy to read.
Do the grayscale test—Contrast is key when it comes to readable text. The highest possible contrast combination available is black letters on a white background, but this gets pretty boring after a while. The thing to watch out for is combining text and background colors that have similar gray values. Although the hues might be different, they still make for difficult reading when put together.
Use moving type sparingly—The best text animation is designed to reinforce a message or make a point. Don't give in to temptation and use text effects to fill time or to serve as a cheap graphics substitute. This is especially true now that cheap FX programs such as Swish have become widely used and abused.
Unfortunately, the written word is often the most overlooked aspect in the Web design process. If you're not a wizard with the word processor, consider hiring a freelance copywriter. You can post your projects cheaply at places such as eLance, where self-employed wordsmiths will be happy to make your site shine.
Don't use monospace fonts or all-caps, except in small doses. People read by recognizing the shapes of whole words rather than letters, and these kinds of fonts require more mental effort.
Do use fonts specially designed for screen text, such as Verdana. In Flash particularly, bitmapped fonts that scale well to smaller sizes (without turning fuzzy) are ideal.
Use Flash's Export Image feature to create grayscale copies of various frames from your movie. If the contrast is low, experiment with new color choices until the text really stands out, especially for headings and navigational elements.