I have joined Link-vault but I am not sure it's good thing to do. I am just not very easy to belive somthing can be done easy way. Can you tell me good and bad sides of this? Any penallities from SE? How much are these links really helping?
The downside is that the links are unstable. If you monitor your links rather then rely on linkvault to tell you whats up you notice that they disapear and stuff and many websites just stop using it ect...
I woudn't recommend it for widespread use on important sites, and definitely don't use it exclusively for promoting a site. I think it is fun to play around with sometimes. Google is pretty savvy about seeing the links. Yahoo and MSN are a little easier to manipulate. Be careful, because there is no guarantee that you wouldn't be banned at some point in the future.
Link-Vault can help if you use it wisely. I once lost a new domain that was solely linked by link-vault members and probably got bad neighborhood from there. On the other hand I know many people who use link-vault to push their established, well-linked projects for certain keywords. For a strong domain a certain percentage of link-vault links doesn't seem to be a problem.
google can identify which is an organic link or not. i think your site will be penalized by google if your links boost at a small time.
Well, I think Google is getting better and better on identifying organic/spoofed links (just read Matt Cutts posts about how they fight link buying). Most of the link you can get from LV are PR0 links from sites with a bad neighbourhood, so I think it's not impossible for Google to filter those links and devalue them. With that not said that LV is useless, not at all, I'm using it myself as a complement to other strategies.