What is Bloatware?
As the wiki excerpt already stated: Bloatware comes pre-installed with many devices. Other than the apps and tools provided by the AOSP Android system itself (see: vanilla-android), these are apps the manufacturer/carrier thinks give "additional value" -- but from most user's point of view only "bloat" the system, slow it down, waste ressources better used in different places, and are after all "unwanted": not everybody needs stock quotes or uses Facebook and Google+, to name some common examples.
It's mostly the carriers doing so, but sometimes already enough of those unwanted apps are provided by the manufacturers.
What can I do to get rid of it?
Starting with Android 4.0, most of the "bloatware" can at least be "disabled": Go to Settings→Apps→Manage Apps, scroll to the unwanted app, open its entry, and hit the "Disable" button -- if not grayed out, indicating "thou shalt not".
Having your device rooted opens a lot of new possibilities. Several apps available on the Playstore allow you not only to "disable" all of those bloatware apps (a process called "freezing", see: freeze-app), but even to completely get rid of them by uninstalling. If going for the latter, one should still freeze such apps for a while to make sure uninstalling won't have any side-effects.
Are there any further recommended readings?
Please check the top questions in this section before asking yours -- it could be your question was already asked and even answered. Especially: