James Fallows makes an interesting point in his "Another step toward the online 'cloud computing' life" post:
Web-based computing has a small disadvantage: working with an online program like, say, Writely (now Google Docs) is slower than using one based on your own machine, since info must constantly go back and forth from a remote server.
In other words, there's a certain value in client/server computing--now considered passe--since the client can perform work locally without always going back to the server. This value add has been true for years, and remains true now. At this point we've been through four generations of client/server architecture (that I know of--there may be more). The first is shrouded in arcane minicomputer history, the second is well-known, the third has been around for several years, and the fourth is happening as we speak.
The first began in the late 1970's, when Wang Laboratories was the equivalent of a dot.com wonder, growing at 100% a year and challenging the incumbent at the time, IBM, within the office market. Its success was due to the combination of a great product (word processor) and a smart architecture (client/server, although no one called it that at the time). Each Wang workstation contained a Zilog Z80 chip, which did a lot of the graphics work required when displaying and editing a document. For example, inserting a character would cause the following characters to move one position to the right, and therefore sometimes cause a word to jump to the next line. Because the Z80 did much of the work, the workstation talked to the server after only every tenth keystroke or so.
This smart design was Wang's secret weapon. For example, although DEC eventually got into the office market, all Wang had to do to beat it in a competitive situation was to suggest to the prospect that it run a test under a heavy workload. Having forty secretaries concurrently pound out memos would bring a VAX to its knees, because every keystroke was a CPU interrupt. On a Wang VS minicomputer, due to the Z80 doing much of the work, 200 typing secretaries was a typical and easily handled workload. Unlike the VAX, the Wang system didn't have a dumb terminal as a front end--it had a smart terminal.