TheOptimizationIdiot - 12:13 am on Apr 21, 2013 (gmt 0)
How does the search engine know that you picked up the phone, called the prestigious .edu site and said Psst! I give student discounts -- as opposed to just cropping up on a list generated by a work-study student assigned to call every business in town and ask if they give student discounts?
They obviously can't "know know" you called and offered a discount, but they don't really need to know "exactly what the manipulation to get the addition was" for it to look manipulative.
When you crop up on a list generated by a work-study student who calls every business, there would likely be a larger "churn" or addition made to the page(s) with the links than a single link being added after a phone call.
One addition on a University site from a phone call offering them/students a discount would likely not be algorithmically detectable, but the link being added to a number of different University's sites without a "triggering event" (like a highly prominent news story) other additions (or churn of links) on their pages seems like it would be fairly easy to detect as "manipulation" of some kind.
Student gets a list and calls a bunch of businesses and yours happens to be one that gets added to the page. The page and linked sites likely change quite a bit on the day(s) the calls are made or when it's updated, meaning there's more than a single link different between the before and after version of the page. (This one would likely appear natural, imo. Website page was updated. It happens.)
Business calls 30 Universities and get's 25 links out of the deal and nothing else changes on the pages containing the link or there are some limited changes to some of the pages and it's the only change on 18 of them. (This would likely appear manipulative, imo. 25 additions of one site by Universities when the site's never been linked from one before and it's not "gaining links all over the place" from a news mention or some other "link triggering event"? Just doesn't seem like it would happen naturally, to me anyway.)