Email is a problem for almost everyone, but in the office in particular, it creates distractions and consumes time that might be better spent doing actual work. Some people refer to checking and responding to email as "doing work about work," rather than doing the work itself.
Business owners and managers can help both themselves and their employees combat email overload at work.
First, encourage face-to-face communication. Getting employees to talk to one another when email isn't necessary can really help reduce needless emails. Face-to-face conversations are also better than email for touchy subjects, when tone and sentiment really matter. Very few people are as adept at conveying their emotions in written language as they are orally.
Second, use an instant messaging program. For quick questions and answers, you really can't beat IM. Some businesses prohibit employees from installing such programs, but I think they are actually a real boon in the office. You can get instant messaging in a standalone app, or one that's built into an online business platform, like Podio, Yammer, Jive. If your organization uses Google Apps, you can always just leverage Google Talk. Whichever IM app you choose, make sure everyone in the organization uses the same thing. And if the IT department has restrictions on what employees can install, make sure that team knows which IM app everyone is supposed to be using so they can verify the installations.
Third, find a better place than email for common messages. One clear example is when employees email to let everyone know they're out sick, on vacation, or leaving early. These are commonplace messages that add to email clutter but don't have to. One solution might be to have a shared calendar. Another might be for an administrative assistant to keep track of who's in and out, and send one consolidated email instead.
Fourth, be an email role model. If you're the head of a company or a department, make sure that your email habits reflect what you want employees to do. Write shorter emails when you can. Speak to people face-to-face when that's the right method of communication. Use IM, and do whatever else you want employees to do. People will follow your lead, and that's how you develop a better company culture around email.