Really good article on backlinks by John Udell:
Offering backlinks is a strategy that furthers the ambition of every blogger to engage other minds. It does so by enlarging the surface area and altering the shape of the posted article, which is the unit of information currency in blogspace.
Both techniques can help provoke the desired engagement which, like a biomolecular reaction, is a hard-won outcome that needs all the catalytic help it can get. The attractive force that binds molecules to substrates is weak, and easily overcome by their incessant jostling. To be effective, writes Loewenstein, "their molecular surfaces must be large, and their shapes must match within a few angstroms."