Even if your name isn't as common as "John Smith," you may be startled to discover how many other researchers in your field have similar names. A 2009 study of author-name ambiguity within the MEDLINE database found that nearly two-thirds of authors had ambiguous names.
The problem is exacerbated in disciplines which cite only first initials, such that "Erin Martinez" and "Edward Martinez" are both cited as "Martinez, E." In addition to commonly occuring names, issues with name confusion may also arise as a result of name changes (e.g., at marriage); transliteration; accents, diacritics, or other special characters in a name; or even simple typos.
Unique identifiers assigned to each researcher helps to disambiguate author names, ensuring that your work can clearly be identified and credited to you. ORCID and ResearcherID are two significant examples of options for establishing a unique author identifier.