Open Source
There is a lot of buzz around open source software right now with all the large investment dollars being poured into open source development efforts by the likes large corporations such as IBM and Google.  Open source software is looking to have a very bright future, with Linux stealing more of the server market every day, and large enterprises choosing to use the open source platforms rather than spend a bunch of money on licensing fees.

Microsoft can no longer claim to do things cheaper and better.  They now have to claim cheaper in the long run, and that is open to large debate.  Sun, which has been floundering around for years, just recently decided to open source large parts of their Solaris x86 operating system.  Sun will probably open source the entire OS after all the legal licensing issues are resolved.  It is yet to be seen if Solaris will gain the popularity of Linux, but certainly it is a big step forward for open source software.

The great thing about open source software is the very low up front startup costs.  This is espically ideal for small to medium sized businesses (SMBs) who don't have a large about of money to spend on IT.

Another great thing about open source software is that there is a large amount of code written to do the tasks that everyone has to do.  So instead of creating a software solution from scratch, you configure pieces of software that have already been written.

Now the question remains, why does anyone invest or create open source software?  From a business stand point it's quite simple.  It's not that these corporations are great people that are trying to do good for human kind, it's because in most cases they are hardware of consulting firms that want to drive down the cost of software so customers have more money to spend with them.