Since 1989, software patents have been allowed into the patent system. This has caused many controversies in recent years and has turned the technology industry into war zone. With the famous the most examples being the ongoing Apple vs Samsung (in a few cases) and Oracle vs Google.
Many of the software patents are trivial. With the patent pool being so big and constantly growing, you wouldn't even know you infringed until the last moment.
From what I understand, the EU prohibits software patents. I think the USA should follow on this one and prohibit software patents too and stop this endless war so we can get back to actual innovation. From what I've heard, the US patent system is apparently up for a reform and I think this should be included.