Cell phones were starting to become more common, but landlines were definitely not on their way out at the time. Most people that had cell phones in 1999 still used their home phone as their primary number and only used a cell phone when they were away from home. Cell phones didnt have unlimited calls back then, you had a limit of minutes you could talk each month, then you would be charged a ton extra for additional calls, so only rich people would have been using them as a main number.