This seems pretty basic and yet people still seem to get this wrong.

If you’re starting a new site, be sure to do a Google search on your desired site name(s) and URLs to make sure the exact name and/or URL, or closely similar names and/or URLs are not already taken. This is particularly important if you plan to use the exact name or a close variant of a popular site in the exact same niche. It only takes a few minutes to do the research. The tools are amazingly easy to use and are completely free.

When you launch a new site, take at least five minutes to do your due diligence.

Being unique is important. If you do something similar to someone else, using the same site name and an only slightly different URL, it’s going to be confusing for the public and it’s going to split search engine results. On top of everything else, it’s not going to do anything to help you build your own unique brand and community.