How come in google my site shows up with different title tags as the ones on my site?

Google's generation of page titles and descriptions (or "snippets") is completely automated and takes into account both the content of a page as well as references to it that appear on the web. The goal of the snippet and title is to best represent and describe each result and explain how it relates to the user's query. We use a number of different sources for this information, including descriptive information in the title and meta tags for each page.

We may also use publicly available information—for instance, anchor text or listings from the Open Directory Project (DMOZ)—or create rich snippets based on markup on the page. While we can't manually change titles or snippets for individual sites, we're always working to make them as relevant as possible. You can help improve the quality of the title and snippet displayed for your pages by following the general guidelines below.

Titles are critical to giving users a quick insight into the content of a result and why it’s relevant to their query. It's often the primary piece of information used to decide which result to click on, so it's important to use high-quality titles on your web pages. As explained above, make sure every page on your site has a title specified in the tag.

If you’ve got a large site and are concerned you may have forgotten a title somewhere, the HTML suggestions page in Webmaster Tools lists missing or potentially problematic tags on your site. Page titles should be descriptive and concise. Avoid vague descriptors like "Home" for your home page, or "Profile" for a specific person's profile.

Also avoid unnecessarily long or verbose titles, which are likely to get truncated when they show up in the search results. Avoid keyword stuffing. It's sometimes helpful to have a few descriptive terms in the title, but there’s no reason to have the same words or phrases appear multiple times.

A title like "Foobar, foo bar, foobars, foo bars" doesn't help the user, and this kind of keyword stuffing can make your results look spammy to Google and to users. Avoid repeated or boilerplate titles. It’s important to have distinct, descriptive titles for each page on your site.

Titling every page on a commerce site "Cheap products for sale", for example, makes it impossible for users to distinguish one page differs another. Long titles that vary by only a single piece of information ("boilerplate" titles) are also bad; for example, a standardized title like " - See videos, lyrics, posters, albums, reviews and concerts" contains a lot of uninformative text. One solution is to dynamically update the title to better reflect the actual content of the page: for example, include the words "video", "lyrics", etc., only if that particular page contains video or lyrics.

Another option is to just use "" as a concise title and use the meta description (see below) to describe your site's content. The HTML suggestions page in Webmaster Tools lists any duplicate titles Google detected on your pages. Brand your titles, but concisely.

The title of your site’s home page is a reasonable place to include some additional information about your site—for instance, "ExampleSocialSite, a place for people to meet and mingle." But displaying that text in the title of every single page on your site hurts readability and will look particularly repetitive if several pages from your site are returned for the same query. ExampleSocialSite: Sign up for a new account.

Be careful about disallowing search engines from crawling your pages. Using the robots. Txt protocol on your site can stop Google from crawling your pages, but it may not always prevent them from being indexed.

For example, Google may index your page if we discover it by following a link from someone else's site. To display it in search results, Google will need to display a title of some kind and because we won't have access to any of your page content, we will rely on off-page content such as anchor text from other sites. If we’ve detected that a particular result has one of the above issues with its title, we may try to generate an improved title from anchors, on-page text, or other sources.

However, sometimes even pages with well-formulated, concise, descriptive titles will end up with different titles in our search results to better indicate their relevance to the query. There’s a simple reason for this: the title tag as specified by a webmaster is limited to being static, fixed regardless of the query. Once we know the user’s query, we can often find alternative text from a page that better explains why that result is relevant.

Using this alternative text as a title helps the user, and it also can help your site. Users are scanning for their query terms or other signs of relevance in the results, and a title that is tailored for the query can increase the chances that they will click through. If you’re seeing your pages appear in the search results with modified titles, check whether your titles have one of the problems described above.

If not, consider whether the alternate title is a better fit for the query. If you still think the original title would be better, let us know in our Webmaster Help Forum. The description attribute within the tag is a good way to provide a concise, human-readable summary of each page’s content.

Google will sometimes use the meta description of a page in search results snippets, if we think it gives users a more accurate description than would be possible purely from the on-page content. Accurate meta descriptions can help improve your clickthrough; here are some guidelines for properly using the meta description. Make sure that every page on your site has a meta description.

The HTML suggestions page in Webmaster Tools lists pages where Google has detected missing or problematic meta descriptions. Differentiate the descriptions for different pages. Identical or similar descriptions on every page of a site aren't helpful when individual pages appear in the web results.

In these cases we're less likely to display the boilerplate text. Wherever possible, create descriptions that accurately describe the specific page. Use site-level descriptions on the main home page or other aggregation pages, and use page-level descriptions everywhere else.

If you don't have time to create a description for every single page, try to prioritize your content: At the very least, create a description for the critical URLs like your home page and popular pages. Include clearly tagged facts in the description.