Anti-aliasing is a standard feature in the industry. Available in AE for completely free.
What exactly is it?
FXAA (also known as Fast approximate anti-aliasing was an anti-aliasing technique invented by Timothy Lottes at NVIDIA. The primary benefit of this method over traditional spatial anti-aliasing is the fact that it does not require a lot of computing capacity (from Wikipedia).
In plain English, FXAA is applied to your final image and is based on pixel data and not on geometry. GPUs are especially fast at running these shader algorithms parallel, making it easy to render.
Why would I need it?
If you've ever experienced an issue with sharp edges (aka jaggies or aliasing, stair stepping) within After Effects, FXAA will take care of them. This is especially true when creating motion trails and motion smears by using The Echo effects as well as Cartoon Motoblur.
