Inbound links or Incoming links, are external sites linking to your site. For example, site A linking to site B, is an example of incoming link or inbound link to site B.
In the early days of web, search engines used to index web pages based on the number of keyword occurrences within a particular web page. This opened the field for spammers who started manipulating search engines by stuffing keywords into title and meta tags. Search engines being one step ahead of spammers found a way around this by putting more emphasis on off page factors like quality and quantity links to a site.
Why are links important ?
Links are, and will continue to remain an important ingredient in Google’s algorithm for ranking sites. This is because they are one of the positive signals to Google about your site’s importance.
This is what Google had to say -
“Your site’s ranking in Google search results is partly based on analysis of those sites that link to you. The quantity, quality, and relevance of links count towards your rating. The sites that link to you can provide context about the subject matter of your site, and can indicate its quality and popularity”
Different Types of links -
One way links – The example given above – site A linking to site B, is an example of one way links – one way link for site B.
Reciprocal links – If site B also links back to site A, then this is an example of reciprocal link.
Three way links – This involves 3 websites A, B and C. In this type of link scheme, site A links to site B, site B links to site C and site C links to site A. Thus each site recieves one way link without linking to each other.