I have some ideas of a blog I want to start, but I don't know how I should go about making sure I'm not accidently stealing someones name. So far some of the things I can come up with are searching google, and making sure I own the .com, .org, and .net. Also, on another note let's assume I have come up with a name that I couldn't find belonging to anyone else, and someone decides to copy it down the road, would I have to have some kind of claim on it via paperwork or would my already established website be good enough to tell them to stop? I'm not sure at all about this, so if I'm missing anything please let me know.
The best way is to pay for a trademark search - a couple of hundred dollars (still not a 100% guarantee). It doesn't matter if a company has a website - it can still be trademark infringement. You basically have to make sure no one else is using the "mark" or a similar spelling - at least in the same classification. Since foreign spellings and phonetic spellings can also be infringement it makes a trademark search very complicated. A trademark also does not need to be registered to have a claim on a name.