Search Link Optimization (SLO) is a process by which internal and external incoming links are optimized for search engine algorithms to determine the relevance of web page content. Relevant anchor text integration, text that contains keywords for optimizing a web page, is key to this process.
Search link optimization Wikipedia
Inbound and outbound links are those that hyperlink two independent web pages together whereas inbound links would hyperlink domain “A” to domain “B” and outbound links would hyperlink domain “B” to domain “A.”
Inbound and outbound links are essential to web page visibility often enhancing web page relevance, ranking, & placement. There are few instances where inbound links would be discouraged. Outbound links however should be given sparingly and should only link material to other material of same or similar relevance. Often, developers will utilize a nofollow tag used mostly to further optimize hyperlinks by “instructing” search engines not to distribute any PageRank from the hyperlink. An example of a nofollow tag might be:
Internal links are those that hyperlink within a single domain. Hyperlinks listed higher within the source code typically gain greater relevance. Some developers use a practice known as PageRank Sculpting by using the nofollow tag to adjust the flow of PageRank.
The mere presence of hyperlinks within a web page may not yield desired optimization results. For example, when coding a web page about "blue widgets," anchor text containing links referencing "red widgets" may alter relevance which can result in gain/loss ranking scenario where “blue widgets” gains while “red widgets” actually loses position. Moreover, another result can be a complete loss of overall web page ranking altogether for either keyword.
A properly coded keyword contains these elements: Relevant anchor text, relevant keyword titling, and compliance-based HTML code structures. Additionally, use of titles that are linked within the title tag is also a recommended practice provided the title tag for the web page has also been properly optimized for the desired keyword(s). Below is the proper coding of a hyperlink: