Does using #section in internal linking affect SEO or crawlability?

Question

On my website, I have several sidebar widgets with internal links relevant to the content. But, the links go to certain sections of a page, not to the whole page.

Example:

http://example.com/page/#section1

#section1 is important as the user will end up right where he needs on the other page, but does this affect crawlability or SEO of the website overall? Or do search engines know that http://example.com/page/ is the actual link to the page and #section1 is used for a different purpose?

Answer 1

Search engines don't crawl fragment IDs. I'd speculate that they "understand" what the fragment ID is doing (i.e. pointing to a specific portion of a page), but I'm not aware of this being stated anywhere in official documentation.

Answer 2

Google does crawl these fragments as you can see on most wikipedia pages as an example when they link to sections of a topic in a table of contents. Perform a Google Search for "list of US states" brings up a Wikipedia page with sitelinks to various sections throughout the page on the topic -- something you are trying to accomplish here.

http://en.wikipedia.org/wiki/List_of_states_and_territories_of_the_United_States

You just need to be sure the #fragment is wrapped in an href as Google can only link to it if its an href. Look at the source code for the above Wikipedia page for an example.

Also, check the clean cache of the page as well as fetching the page in GWT to see if the links are crawled. Here is the clean cache of this Wikipedia page: http://webcache.googleusercontent.com/search?q=cache:http://en.wikipedia.org/wiki/List_of_states_and_territories_of_the_United_States&hl=en&strip=1

Lastly, be sure actually want to make the content of your page accessible via an on-page anchor rather than living on its own page. You can run into backlink issues when using this scheme so using it for UX is ok but if the content can live on its own then I suggest creating a new page for it.