I thought it would be a good idea to post this article that I found not to long ago. *NOTE*: I didn't write this article nor did I help in any way. Please give credits to the Terence Tan.
I don't know... while that may generate some traffic, those doorway pages would likely take a while to catch up to other sites worth reading that discuss your competitor. I'd assume that making use of quality content should shoot you right up there when consumers are looking for your keywords. Though honestly, if I am looking for siteA.com and come across some sales pitch from siteA.info or even siteB.com that is doing something like that, you can bet it's going on my "do not buy" list and they are certainly not getting a christmas card from me either! LOL
This is risky as you are gonna use a trademark or namesake..it should be assumed since you are competitors u are using the same kw.. A better idea is using negative kw bombing on your competitor using their url.. ie..do a massive link campaign for their url to a kw not related- example- you guys sell tires? do a kw link campaign for your competitor for t shirts. ps- alot of the BIG guys do this. And yes it works.
when you say "do a massive link campaign for their url to a kw" can you clarify a bit more about what you mean. If you're indicating he should go out and do forum/blog posts about tshirts linking to the tire site, that sounds like an awful lot of effort. please explain more
Isn't this one of the tactics that falls under the umbrella of Google Bowling? Pretty crappy tactic. I'd like to think that Google could put their big brains together and figure out a way to detect 3rd party schemes like this, but apparently they have too much on their hands tracking down paid back links. :-p
I've got one major (more established) competitor for my main site. Most of his writers are now writing on my site and he is really pissed off about it. I actually thought about adding some keyword rich pages to draw traffic from his site, but I don't want him to have a heart attack. Using a doorway page like that is quite sneaky and could probably land you in a lot of hot water.