Inbound links play a key role in determining search engine rankings. The quality of links matters more than just the quantity, with more authoritative, topically relevant pages carrying more weight. PageRank is Google's algorithm that measures page importance, with pages on sites like Google and Yahoo scoring highest. Getting links from .edu, .gov, and other authoritative sites provides the most benefit. The best links are one way, topically relevant, and not overcrowded on pages. Participating in link schemes or farms undermines rankings.