FORT LAUDERDALE — When people think of libraries, free-standing buildings with books, computers and other media may come to mind. In fact, nearly 30,000 people a day use Broward libraries, and throughout the year more than five million library books are in circulation.

But behind those library walls is Broward County Library Without Walls, or BCL WOW.  Broward County provides a virtual library that grows in popularity as today’s culture increasingly makes use of computers, laptops, tablets and mobile phones. Library cardholders can renew books online, download e-books and audio books and have instant access to a variety of journals. More than 119,000 e-books and audio books were downloaded last year, a 1,000-percent increase from the year before.

Miami-Dade and Palm Beach counties’ public library systems report similar numbers, for digital offerings “that are compatible with any mobile digital device,” said Max McMillan, the latter system’s public information officer. “All you need to access the collection is a Palm Beach County library card and the free software.”

With the ability to bring a virtual library right into any home, Broward’s library website receives 700,000 electronic visitors a month. The Miami-Dade Public Library System gets 880,000-plus, said Victoria Galan, their public information officer. “You may not need to come through our door,” she said, “but you can come to our website.”