gets your website pushed near the top on google
...and that's a load of crap. Google are aware of all the tricks, and anyone abusing them gets a black mark, and withdrawn from there database. New site are sandboxed for about 8 months, so your not even ranked. It takes a lot of hard work.

The majority of those companies sell information that is out-of-date, as Google change the rules every 3 months, and it took folk 6 months to work out the sandboxing....by then....things have changed again. They changed it big in Feb, all links rated less than 4, then became a value of zero, so millions of sites have dropped.....and are still doing so...Google have started a cascade.