Software developers often start with a nice simple program. They will add features to this program as they see fit, until it fulfills all the functions required of it. If this program falls into the hands of MarkeTroids however, 4 billion spurious features will be added to the program just to force the end user to upgrade to the latest and greatest version. This is known as Bloat. It is the reason "todays" software is hundreds of times larger and much slower than older versions, despite exponential increases in the hardware it runs on. Developers - combat with AntiBloat.

Zawinski's Law
"Every program attempts to expand until it can read mail. Those programs which cannot so expand are replaced by ones which can." Coined by JamieZawinski (who called it the "Law of Software Envelopment") to express his belief that all truly useful programs experience pressure to evolve into toolkits and application platforms (the mailer thing, he says, is just a side effect of that). It is commonly cited, though with widely varying degrees of accuracy.

Now it is that every program attempts to expand until it can surf the web. These programs which cannot so expand are replaced by ones which can. -- PerryLorier

For example, both the GNOME and KDE desktops can often feel bloated on older/slower computers. Part of this could be attributed to developers having high-spec machines when writing/testing software. To pick on GNOME, here are some examples of memory usage:

|Process Name|Virtual Memory|Shared|Notes |galeon-bin|100MB|33MB|One browser window, 4 tabs open |gconfd-2|21280KB|5140KB| |rhythmbox|65356KB|18MB|781 songs in playlist |gedit|24708MB|17MB|on startup, no files open

Granted they are sharing lots of memory with other processes, but the amount of memory allocated solely for each program still seems quite large - gedit is using 7MB of its own just to display a menu, toolbar, and a text area for typing!

And then there’s Proprietary software, which seems determined to make modern hardware run just as slowly as old hardware. Read The Great Moore’s Law Compensator, and weep...