Page titles have always been a very important part of Google’s search results, because they are not only a part of Google’s ranking algorithm, but they are also visible in search engine results and they’re the actual clickable links Google searchers click to reach sites. Many webmasters are curious about why Google sometimes show alternative titles in it’s search results. A lot of SEO specialists are pissed about this, but generally everyone will benefit from this update. Google explains it in Better page titles in search results blog post and the updated Site title and description article in Google’s Help Center .
2 important factors for webmasters:
1. Google algorithms produce thee substitute page titles so that your web page is no longer constrained with using just the single title for all the different searches your web page ranks for. This has the nice side effect of generating the search result appear more relevant to Google searchers.
2. The alternative page titles improve the clickthrough rate on the results
The <title> HTML tag is still the main source for page titles Google shows so Google’s advice about make them useful and appealing still apply
