The reason behind this is that bots are, and have been, built to be simple creatures by nature, unable to crawl more advanced code, and other rich content such as images and flash. Perhaps this was partly done to save on processing and memory usage, though it can be imagined that indexing the entire Internet raises some tough logistical questions that need to be worked out, to ensure a stable environment. The “Big 3″ or Tier 1 Search Engine companies have Datacenters the size of football fields, many times over, but before we continue in such broad strokes, how about a small test.
Looking at this test meta page result in Google, the title tag is displayed.
Practical Uses for JS