Software developers, whether for desktop platforms, mobile devices, or web services, inherently need to use a lot of pieces of information as part of their daily routine.
These scraps might include IP addresses, server names, configuration strings, and code snippets.
My typical approach used to be to store all of that in plain text files, since I can easily search for them using Spotlight, and it's easy to create/edit them. The downside is that each time I need one, I need to open the text file, highlight the text, copy it, switch back to the application where I will use it, and paste the text. Sometimes I need multiple things from one text file, and sometimes I need multiple things from multiple files. It's hard on the wrist! :P
Et voila! Une solution! Since version 10.6 (Snow Leopard), Mac OS X has had a global text substitution feature. It can be found at its System Preferences pane, found in the Language & Text section under the Text tab. It allows text to be dynamically replaced in the vast majority of programs, even non-Apple ones such as Skype, although it might have to be enabled from the program's Edit->Substitutions menu.
Now, an entry could be added to the system pref pane mentioned above to map
192.168.0.15. From then on, wherever text substitutions are enabled, you can save yourself the extra keystrokes. The downside is it doesn't work in some important applications like Firefox for whatever reason.
Note that if you need something like this but on a much larger scale, you should check out other third-party solutions such as TextExpander. Not only will they be much more powerful, their settings will be easier to modify than Apple makes theirs.
Let me know if and how you use Mac OS X's text substitution feature in the comments. Mention any alternative products you use, too!