A permalink (permanent link) is a type of URL (Uniform Resource Locator) set up for a specific item of information, often a news story or weblog item.
The Graphics Shop Blog has a permalink for each blog entry for referencing that specific entry instead of the entire blog. If you find an item of particular interest to you while reading The Graphics Shop Blog, you can click on the permalink and bookmark it. For example, you might want to bookmark an entry that includes a special promotion code.
Wikipedia, the free encyclopedia, has a more detailed explanation on Permalinks.