I have a website that allows users to display their email address and contact number on their public profile page. These would be in link format, example:
<a href="mailto:user%40email.com" title="email user">[email protected]</a>
<a href="tel:+123456789" title="call user">+123456789</a>
I was wondering if it is necessary at all to add a rel="nofollow" tag to these. Do search engines follow and index these?
Most commonly mistaken thing about the 'nofollow' tag is that has nothing to do with not indexing content. I recommend you read the true meaning of nofollow.
Also technically email addresses and tel links are internal links so there should be no reason to use a nofollow tag on it. Furthermore, mailto and tel are not pages or links to content in any way.
If you don't want email addresses being indexed then you should add that content dynamic and after the page has loaded, or alternatively use some form of JavaScript that Google and other search engines don't understand.
noindex and robots.txt. This has the limitation of deindexing or preventing pages from indexing, there is no way of preventing content being indexed on a page that you want indexed, other than using black techniques which should be avoided if you care about your rankings. The best method would be to use JavaScript, through Google will understand most JS as John has mentioned but most non-advance scrapper bots will not see it lowering the spam.
Commented
Nov 2, 2013 at 15:07
site:domain.com + "[email protected]" it is likely to be indexed in a content manner.
Commented
Nov 2, 2013 at 15:10
nofollow on these internal links, I am fine. From what you wrote, I should be able to conclude that tags on these are indeed redundant. Thanks.
Commented
Nov 2, 2013 at 16:42
Now search engine are able to index mostly everything, even some JavaScript code, except if encrypted. If you don't want to disturb your clients and lose your PageRank you can read these excellent answers: https://stackoverflow.com/a/12566551/2491683 - or search in Google for the query: encrypt a link.
href of mailto. But this is not what I am asking.
Commented
Nov 2, 2013 at 14:38
You can tell Google in your HTML markup to ignore a section of HTML.
<!-- googleoff: all-->
<a href="mailto:user%40email.com" title="email user">[email protected]</a>
<a href="tel:+123456789" title="call user">+123456789</a>
<!-- googleon: all-->
That will prevent that piece of HTML from appearing in the cache or being indexed. It offers no security and is only supported by Google.
You can perform Javascript based obfuscation of the email. Here is a jQuery plugin that does that.
https://github.com/mikebranski/jquery-nospam
Alternately, you can do the opposite and share contact information in a way they can index more effectively. Using the hCard microdata format.
http://microformats.org/wiki/hCard
The only way to prevent webcrawlers from accessing this information is to only show it to authorized user sessions that have been verified as humam. Even that is a challenge.
@in the email address?mailtoURI. Between the local-part and the domain-part there needs to be a@character. If the local-part contains a@, it needs to be percent-encoded (%40) and the local-part needs to be enclosed in quotation marks (%22) (there may also be other ways, e.g. backslash escaping, but I didn’t check that).