Changes to SEO with disavow?

[BobAnderson]

Has the game changed a lot with the disavow tool I can see people still saying check out what our competitors are doing but with just going through a disavow myself how do you actually know what the correct link diversity is as 0 - 100% of the links could be disavowed.

Also could a competitor not just buy a load of spammy links and disavow them to mask there real links. (I know in my backlinks on 150 are good and the rest is disavowed crap)

[Chris.Menke]

Would you buy a bunch of spammy links and point them at your own site just so you could disavow them and try to fool your competitors?  Not likely because it's hard to fool anyone who's knowledgeable about links about the quality of the links they're looking at when they actually visit the linking site/page and a strong competitor isn't going to chance a penalty on a technique such as that.