A few weeks ago, it was discovered that Sony was in the process of trying to trademark the term ‘Let's Play', despite the fact that it is a generic term used by the gaming community at large. At first, the US Patent and Trademark Office told Sony that it would need more information before allowing the trademark but following a letter of protest from a law firm, Sony won't be able to trademark the term at all in the US.
Following widespread reports of Sony trying to trademark Let's Play, the McArthur law firm sent a letter of protest to the USPTO detailing a few key arguments as to why Sony should not get the trademark.
The most important argument made was that the term is generic descriptor at this point, meaning it can't be used as a brand name or trademarked. Aside from the McArthur lawfirm's letter, the US patent office also checked the Wikipedia page for Let's Play as well as the /r/letsplay subreddit for further evidence.
Sony can challenge the ruling within six months but at this point, it looks unlikely that it will be able to overcome this rejection.
KitGuru Says: This move from Sony has seen heavy opposition and now, it looks unlikely that any company will be able to trademark the term Let's Play now that it is being considered as a generic descriptor in the US. It will be interesting to see if Sony gives up or if it attempts to challenge the ruling within the next six months.