The number of employees that use instant messaging to communicate with co-workers while at the office rose sharply last year, according to a new survey sponsored by AOL.In the 2004 survey, 27% of IM users said they used this instantaneous, abbreviated form of electronic communications while at work. This figure is up from last year, when 16% of survey respondents said they used IM for work-related communications.Seventy-one percent of at-work IM users say it has had a positive impact on their work lives. A majority of at-work IM users, 70%, say they use IM to communicate with colleagues, while 34% say they use IM to communicate with clients or customers.Meanwhile, business travel is driving much of the IM usage on mobile devices. More than 30% of mobile messengers say they stay in touch with co-workers via mobile IM or SMS text messages while traveling for work. In the 2004 survey, 19% of survey respondents say they send IMs from mobile devices, up from 10% last year.Still, the majority of IM usage is for personal communications. Ninety percent of survey respondents send instant messages to keep in touch with family and friends, while 28% use IM to send photos.Even while at work, some IM usage is personal. Nearly two-thirds of at-work IM users say they send occasional IMs to check in with family and friends, and 21% say they have flirted via IM while at work.\u201cInstant messaging has become part of the fabric of our daily lives, enabling all the roles we play from student to best friend, from parent to busy professional,\u201d Edmund Fish, senior vice president and general manager of desktop messaging at AOL, said in a statement. \u201cIt\u2019s helping people do everything from spark new relationships to increase their productivity at work.\u201dOther key findings of the survey are:* IM is going mainstream with greater usage among older Americans. While 90% of teens and young adults engage in IM, 48% of those ages 55 and older now use IM, particularly to share photos. Among Internet users ages 22 to 34, 71% use IM and among those ages 35 to 54, 55% use IM.* The top 10 cities for IM usage are: New York; Miami; Chicago; Philadelphia; Orlando, Fla.; Dallas\/Fort Worth; Atlanta; Washington, D.C.; Los Angeles and Houston. (Surprisingly, high-tech meccas San Francisco, Seattle and Boston did not make the top 10.)The second annual IM trends survey covered all IM usage, not just usage of AOL\u2019s IM platforms. Opinion Research Corp. conducted the survey of 4,500 IM users in June and July.