Link bait is any content or feature, within a website, designed specifically to gain attention or encourage others to link to the website. Matt Cutts defines link bait as anything "interesting enough to catch people's attention."[1] Link bait can be an extremely powerful form of marketing as it is viral in nature.
Link Pyramid means level of link building. There are 5 levels of link building and in every level you have to do different link building like in !st level you have to directory submission after that in next level you try different link building technique.