Planet13 - 6:46 pm on Jul 5, 2011 (gmt 0)
I'm thinking only sites that buy more and more links each month will be penalized to get around this - a one off link buy would not be enough to trip this up.
for what it's worth, in the various black hat forums, they say that the best way to avoid being penalized is to buy link blasts on a regular bases.
They say that doing a one-off link blast is the most likely way to be penalized, since it will be so easy to spot.
Anyway, that's just what the black hatters say.