When talking about the weight of a link, its importance (validity) is implied from the point of view of search engines.

Weight which external links bring to an promoted site, increase its own total weight, affect "Puzomerics" (tis and PR), taken into account when ranking search issue.

The quantitative determination of the weight of the link depends on the level authority donor, as well as him thematic, the number of other outgoing links, anchora and link location.

Outgoing links can take weight from the website. For a successful progress the number of such links should be minimal.