In the context of the World Wide Web, deep-linking consists of using a hyperlink that links specific, generally searchable or indexed, pieces of web content on a website. For example, the home page of any website is the top level page in the hierarchy of pages that is typically denoted as an “Index Page.” Any page, other than that top level page, is then considered “Deep.” Most websites on the Internet have depth, but not all.
Think of your “Home Page” as a needle in a digital haystack of data; what are the odds of being found? Back-links are the equivalent, in theory, to word-of-mouth marketing. In theory, when someone communicates by pointing out any particulars about a people, place and/or thing, they are, in effect, promoting that entity. Back-links are essentially that.
Word-of-mouth marketing is the best form of marketing, because it’s an unpaid form of promotion; oral and/or written, in which satisfied and/or unsatisfied customers tell other people how much they like and/or dislike a business, product, and/or service. Deep-linking is as important as back-linking is, and can be one in the same. Any one of your pages has the potential to bring in visitors, and if those visitors like what they sense, they’re more likely to stick around; potentially drawing others.
Some problems you may encounter while promoting deep-linking read as follows: Webmasters are generally lazy; taking the path of least resistance. It’s far easier to link a home page and request that the reciprocating party do the same. Even in most directories, the vast majority of them will only allow you submit your home page in exchange for a reciprocating link that links their home page. As a footnote: Directories may place your link deep; never to be seen, and prohibit you from doing the same.
Even if webmasters allow a deep-link, and allow you to reciprocate in the same fashion, they might only allow that single submission, for example. Each link within a hierarchy of links on a website has page rank; each contributing and/or subordinating their personal prominence to the efficiency of the whole domain. The top three search engines like Bing, Yahoo, and Google are masters who rely heavily on automation who are also blinded by corporate greed. There’s nothing autonomous about Corporate America.