Don't be intimidated. Some of the best-educated people say the most ridiculous things, so join humanity!

(And BTW, you express yourself better than most.)
Searching the trademark forum for "likelihood of confusion" should bring up some good discussions to get you started in learning about this. Also, you could see if "trademark use" or "registered trademark" might bring up discussions of how trademark rights develop in the US. (Here, rights are based on use, and first in time is first in right. They are NOT created by trademark registration, although an intent-to-use (ITU) application can get you "dibs" on a mark dating from the application date instead of first actual use.)
Apart from that, here's a snippet of TM wisdom in a nutshell:
In trademarks, context is all-important, marks don't have to be exactly the same to conflict. Basic concept is that we don't want businesses to
1) fool or confuse the public as to the source of their goods or
2) take a free-ride on someone else's hard-won branding or
3) nastily tarnish someone else's good name.
So, a birds-eye view of an infringement analysis based on likelihood of confusion would go something like this...
-You look at the competing marks themselves--what they look, sound, (sometimes even smell) like. What's the total commercial impression?
-Then you look at the goods or services. Do they compete with each other or are they really different? Will people likely think the new brand is related to the older one?
-Into this mix you figure whether the first mark is really unique or has been around a long time and become famous and is identified in the public mind with that one business.
With that information, you decide whether or not there is a likelihood of confusion.
Microsoft is pretty famous and unique as a name. If it's likely consumers will think "Microsoft planet" has to do with the famous software giant, you can be pretty sure it would count as infringing.