First and most important, we think it is the best available video codec today for HTML5 for our customers. Relative to alternatives, H.264 maintains strong hardware support in PCs and mobile devices as well as a breadth of implementation in consumer electronics devices around the world, excellent video quality, scale of existing usage, availability of tools and content authoring systems, and overall industry momentum – each an important factor that contributes to our point of view. H.264 also provides the best certainty and clarity with respect to legal rights from the many companies that have patents in this area.
The article goes into detail for each of these points and is an interesting read, confirming a lot of points already discussed here."
Link to Original Source